CVE-2026-72251
netfilter: nf_nat_sip: reload possible stale data pointer
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_nat_sip: reload possible stale data pointer quoting sashiko: ------------------------------------------------------------------------ [..] noticed a potential memory bug and header corruption involving the SIP NAT helper. In net/netfilter/nf_nat_sip.c:nf_nat_sip(): if (skb_ensure_writable(skb, skb->len)) { nf_ct_helper_log(skb, ct, "cannot mangle packet"); return NF_DROP; } uh = (void *)skb->data + protoff; uh->dest = ct_sip_info->forced_dport; if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, protoff, 0, 0, NULL, 0)) { If a cloned or fragmented SKB is reallocated by skb_ensure_writable(), the old data buffer is freed. However, nf_nat_sip() fails to update *dptr to point to the new buffer. It also appears to use nf_nat_mangle_udp_packet() on what could be a TCP packet, which would overwrite the sequence number with a checksum update. ------------------------------------------------------------------------ nf_conntrack_sip linerizes skbs, hence no fragmented skb can be seen. But clones are possible, so rebuild dptr. Disable nf_nat_mangle_udp_packet() branch for TCP streams. It doesn't look like this can ever happen, else we should have received bug reports about this, so just check the conntrack is UDP and drop otherwise. The calling conntrack_sip set ->forced_dport for SIP_HDR_VIA_UDP messages, so I don't think this is ever expected to be true for a TCP stream.
INFO
Published Date :
Aug. 15, 2026, 6:21 a.m.
Last Modified :
Aug. 17, 2026, 6:18 a.m.
Remotely Exploit :
Yes !
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Update the Linux kernel.
- Rebuild dptr for cloned SKBs.
- Disable mangling for TCP packets.
- Verify conntrack is UDP.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-72251.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-72251 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-72251
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-72251 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-72251 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 17, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': 'bded21a4bf9bf86a79148be735723a97ca9a7532', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': 'dc11f26685aa850f237226f0f463647aea58ab7c', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': 'e38143c9b477f2968024c47c647dd4456a40aff1', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': '57e4e29644ec054d7021d296407e7ddd844afea2', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': 'eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': '2bcf2c5052fb5e73e255140ab43f056aef409c27', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': '0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': '77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68', 'versionType': 'git'}], 'programFiles': ['net/netfilter/nf_nat_sip.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3.9'}, {'status': 'unaffected', 'version': '0', 'lessThan': '3.9', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc3', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/netfilter/nf_nat_sip.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': 'bded21a4bf9bf86a79148be735723a97ca9a7532', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': 'dc11f26685aa850f237226f0f463647aea58ab7c', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': 'e38143c9b477f2968024c47c647dd4456a40aff1', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': '57e4e29644ec054d7021d296407e7ddd844afea2', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': 'eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': '2bcf2c5052fb5e73e255140ab43f056aef409c27', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': '0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': '77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68', 'versionType': 'git'}], 'programFiles': ['net/netfilter/nf_nat_sip.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3.9'}, {'status': 'unaffected', 'version': '0', 'lessThan': '3.9', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/netfilter/nf_nat_sip.c'], 'defaultStatus': 'affected'}] -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 15, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': 'bded21a4bf9bf86a79148be735723a97ca9a7532', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': 'dc11f26685aa850f237226f0f463647aea58ab7c', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': 'e38143c9b477f2968024c47c647dd4456a40aff1', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': '57e4e29644ec054d7021d296407e7ddd844afea2', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': 'eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': '2bcf2c5052fb5e73e255140ab43f056aef409c27', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': '0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7', 'versionType': 'git'}, {'status': 'affected', 'version': '7266507d89991fa1e989283e4e032c6d9357fe26', 'lessThan': '77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68', 'versionType': 'git'}], 'programFiles': ['net/netfilter/nf_nat_sip.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3.9'}, {'status': 'unaffected', 'version': '0', 'lessThan': '3.9', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc3', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/netfilter/nf_nat_sip.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_nat_sip: reload possible stale data pointer quoting sashiko: ------------------------------------------------------------------------ [..] noticed a potential memory bug and header corruption involving the SIP NAT helper. In net/netfilter/nf_nat_sip.c:nf_nat_sip(): if (skb_ensure_writable(skb, skb->len)) { nf_ct_helper_log(skb, ct, "cannot mangle packet"); return NF_DROP; } uh = (void *)skb->data + protoff; uh->dest = ct_sip_info->forced_dport; if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, protoff, 0, 0, NULL, 0)) { If a cloned or fragmented SKB is reallocated by skb_ensure_writable(), the old data buffer is freed. However, nf_nat_sip() fails to update *dptr to point to the new buffer. It also appears to use nf_nat_mangle_udp_packet() on what could be a TCP packet, which would overwrite the sequence number with a checksum update. ------------------------------------------------------------------------ nf_conntrack_sip linerizes skbs, hence no fragmented skb can be seen. But clones are possible, so rebuild dptr. Disable nf_nat_mangle_udp_packet() branch for TCP streams. It doesn't look like this can ever happen, else we should have received bug reports about this, so just check the conntrack is UDP and drop otherwise. The calling conntrack_sip set ->forced_dport for SIP_HDR_VIA_UDP messages, so I don't think this is ever expected to be true for a TCP stream. Added Reference https://git.kernel.org/stable/c/0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7 Added Reference https://git.kernel.org/stable/c/2bcf2c5052fb5e73e255140ab43f056aef409c27 Added Reference https://git.kernel.org/stable/c/57e4e29644ec054d7021d296407e7ddd844afea2 Added Reference https://git.kernel.org/stable/c/77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68 Added Reference https://git.kernel.org/stable/c/bded21a4bf9bf86a79148be735723a97ca9a7532 Added Reference https://git.kernel.org/stable/c/dc11f26685aa850f237226f0f463647aea58ab7c Added Reference https://git.kernel.org/stable/c/e38143c9b477f2968024c47c647dd4456a40aff1 Added Reference https://git.kernel.org/stable/c/eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17