CVE-2026-74598
ipv6: fix Route Information option length validation
Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: fix Route Information option length validation rt6_route_rcv() validates the Route Information option (RFC 4191) length against the prefix length, but both checks are off by one. rinfo->length is the ND option length in units of 8 octets and it *includes* the 8-byte option header, so an option carrying N bytes of prefix has length == 1 + N/8. RFC 4191 section 2.3 requires length 3 when Prefix Length is greater than 64, and 2 or 3 when it is greater than 0. The code accepts length >= 2 and length >= 1 respectively. ipv6_addr_prefix() then copies prefix_len/8 bytes out of rinfo->prefix, so a Router Advertisement with (prefix_len=128, length=2) or (prefix_len=64, length=1) makes the kernel read up to 8 bytes past the end of the option. Those bytes end up in the prefix of the route that gets installed, so they are visible to userspace: # RA with a Route Information option (prefix_len=128, length=2) # followed by a source link-layer address option, 01 01 de ad be ef ca fe $ ip -6 route show 2001:db8:dead:beef:101:dead:beef:cafe via fe80::1234 dev veth0 proto ra ^^^^^^^^^^^^^^^^^^ the next option, read out of bounds When the Route Information option is the last one in the packet, those eight bytes come from the skb tail room instead. Reject the option lengths RFC 4191 does not allow.
INFO
Published Date :
Aug. 22, 2026, 4:16 p.m.
Last Modified :
Aug. 22, 2026, 4:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Apply the patch for ipv6: fix Route Information option length validation.
- Update the Linux kernel to the latest version.
- Validate Route Information option lengths against RFC 4191.
- Reject invalid option lengths.
References to Advisories, Solutions, and Tools
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CVE-2026-74598.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-74598 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-74598
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).
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The following list is the news that have been mention
CVE-2026-74598 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-74598 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.
-
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 22, 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': '70ceb4f53929f73746be72f73707cd9f8753e2fc', 'lessThan': '2f6f94eda12430fb41b24b44a71e2ea4e93561d7', 'versionType': 'git'}, {'status': 'affected', 'version': '70ceb4f53929f73746be72f73707cd9f8753e2fc', 'lessThan': '7eac87396c44a312be457ef41d4c5687883be9a2', 'versionType': 'git'}, {'status': 'affected', 'version': '70ceb4f53929f73746be72f73707cd9f8753e2fc', 'lessThan': '7309529f257ae18e72112ef9f614edfd6df229bb', 'versionType': 'git'}, {'status': 'affected', 'version': '70ceb4f53929f73746be72f73707cd9f8753e2fc', 'lessThan': '0b9e02f3bd31c888f2ccdc0ca08e546d6abe9c4d', 'versionType': 'git'}, {'status': 'affected', 'version': '70ceb4f53929f73746be72f73707cd9f8753e2fc', 'lessThan': 'ff3cb05289b8a4ef95fa7ea14c7d34818359edbb', 'versionType': 'git'}, {'status': 'affected', 'version': '70ceb4f53929f73746be72f73707cd9f8753e2fc', 'lessThan': '3b2231e358d26e3aec5d8040b1fb777af03c5f05', 'versionType': 'git'}, {'status': 'affected', 'version': '70ceb4f53929f73746be72f73707cd9f8753e2fc', 'lessThan': 'da64ed1f346ba84df574d6469fa2e422b2511719', 'versionType': 'git'}, {'status': 'affected', 'version': '70ceb4f53929f73746be72f73707cd9f8753e2fc', 'lessThan': 'd1ad8fb2ac6a1afb71dc22d9ae8efb4dda96c824', 'versionType': 'git'}], 'programFiles': ['net/ipv6/route.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '2.6.17'}, {'status': 'unaffected', 'version': '0', 'lessThan': '2.6.17', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.265', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.216', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.183', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.152', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.104', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.45', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.9', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/ipv6/route.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: ipv6: fix Route Information option length validation rt6_route_rcv() validates the Route Information option (RFC 4191) length against the prefix length, but both checks are off by one. rinfo->length is the ND option length in units of 8 octets and it *includes* the 8-byte option header, so an option carrying N bytes of prefix has length == 1 + N/8. RFC 4191 section 2.3 requires length 3 when Prefix Length is greater than 64, and 2 or 3 when it is greater than 0. The code accepts length >= 2 and length >= 1 respectively. ipv6_addr_prefix() then copies prefix_len/8 bytes out of rinfo->prefix, so a Router Advertisement with (prefix_len=128, length=2) or (prefix_len=64, length=1) makes the kernel read up to 8 bytes past the end of the option. Those bytes end up in the prefix of the route that gets installed, so they are visible to userspace: # RA with a Route Information option (prefix_len=128, length=2) # followed by a source link-layer address option, 01 01 de ad be ef ca fe $ ip -6 route show 2001:db8:dead:beef:101:dead:beef:cafe via fe80::1234 dev veth0 proto ra ^^^^^^^^^^^^^^^^^^ the next option, read out of bounds When the Route Information option is the last one in the packet, those eight bytes come from the skb tail room instead. Reject the option lengths RFC 4191 does not allow. Added Reference https://git.kernel.org/stable/c/0b9e02f3bd31c888f2ccdc0ca08e546d6abe9c4d Added Reference https://git.kernel.org/stable/c/2f6f94eda12430fb41b24b44a71e2ea4e93561d7 Added Reference https://git.kernel.org/stable/c/3b2231e358d26e3aec5d8040b1fb777af03c5f05 Added Reference https://git.kernel.org/stable/c/7309529f257ae18e72112ef9f614edfd6df229bb Added Reference https://git.kernel.org/stable/c/7eac87396c44a312be457ef41d4c5687883be9a2 Added Reference https://git.kernel.org/stable/c/d1ad8fb2ac6a1afb71dc22d9ae8efb4dda96c824 Added Reference https://git.kernel.org/stable/c/da64ed1f346ba84df574d6469fa2e422b2511719 Added Reference https://git.kernel.org/stable/c/ff3cb05289b8a4ef95fa7ea14c7d34818359edbb