CVE-2026-74269
bnxt: fix head underflow on XDP head-grow
Description
In the Linux kernel, the following vulnerability has been resolved: bnxt: fix head underflow on XDP head-grow The xdp.py test test_xdp_native_adjst_head_grow_data crashes when run on a bnxt machine (and also crashes in NIPA). It seems that the bug is an underflow in bnxt_rx_multi_page_skb, which builds the skb head: napi_build_skb(data_ptr - bp->rx_offset, rxr->rx_page_size); The problem with this expression is that in page mode, rx_offset is: bp->rx_offset = NET_IP_ALIGN + XDP_PACKET_HEADROOM; Which evaluates (at least on x86_64) to 258. The test test_xdp_native_adjst_head_grow_data tests a case where the head is adjusted by -256. When this test runs, data_ptr is shifted to frag_start + 2 (where frag_start = page_address(page) + offset). Then, bnxt_rx_multi_page_skb is invoked and the napi_build_skb expression subtracts 258, landing at an address before frag_start. This could be either the previous fragment or the previous physical page when the offset is < 256 (e.g. if the fragment started at offset 0). When the skb is freed, the page pool fragment reference is dropped on either the wrong page or the wrong frag of the right page. In either case, the corrupted reference count can lead to the page being prematurely recycled while still in use. Once (incorrectly) recycled, it can be handed out again and on driver teardown this would result in a double free. The commit under fixes updated this code to handle the case where the native page size is >= 64k, but it unintentionally broke the head grow case. To fix this, add an offset field to struct bnxt_sw_rx_bd, mirroring the existing offset field in struct bnxt_sw_rx_agg_bd. Populate it on allocation and preserve it on reuse. In bnxt_rx_multi_page_skb, use the newly added offset field to compute the fragment start and pass that to napi_build_skb. Adjust the layout with skb_reserve. There are two cases, the non-adjustment case and the adjustment case. In both cases, the skb is built at page_address(page) + offset to account for the case where the native page size >= 64K and skb_reserve is called with data_ptr - (page_address(page) + offset). That difference equals bp->rx_offset when data_ptr was not moved, or bp->rx_offset + xdp_adjust when XDP adjusted the head. Re-running the failing test with this commit applied causes the test to run successfully to completion. The other rx_skb_func implementations don't have this issue.
INFO
Published Date :
Aug. 15, 2026, 6:22 a.m.
Last Modified :
Aug. 17, 2026, 6:19 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 bnxt_rx_multi_page_skb to use a new offset field.
- Populate the offset field on allocation and reuse.
- Compute fragment start using the offset field.
- Adjust layout with skb_reserve.
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-2026-74269.
| URL | Resource |
|---|---|
| https://git.kernel.org/stable/c/bb72b1c6755631c74b7e0878ee55bb81c06776c0 | |
| https://git.kernel.org/stable/c/e26657fe3b85c068b01f42bb0c602f242d643ba9 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-74269 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-2026-74269
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-2026-74269 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-74269 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': 'f6974b4c2d8e1062b5a52228ee47293c15b4ee1e', 'lessThan': 'bb72b1c6755631c74b7e0878ee55bb81c06776c0', 'versionType': 'git'}, {'status': 'affected', 'version': 'f6974b4c2d8e1062b5a52228ee47293c15b4ee1e', 'lessThan': 'e26657fe3b85c068b01f42bb0c602f242d643ba9', 'versionType': 'git'}, {'status': 'affected', 'version': 'e9f11bfc03fb0d3c86f91b8ae945bb10f7e19c16', 'versionType': 'git'}, {'status': 'affected', 'version': 'ae0e135dc900827687ecc684c2bbb57aae48d318', 'versionType': 'git'}, {'status': 'affected', 'version': '6.1.45', 'lessThan': '6.2', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.4.10', 'lessThan': '6.5', 'versionType': 'semver'}], 'programFiles': ['drivers/net/ethernet/broadcom/bnxt/bnxt.c', 'drivers/net/ethernet/broadcom/bnxt/bnxt.h'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.5'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.5', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/net/ethernet/broadcom/bnxt/bnxt.c', 'drivers/net/ethernet/broadcom/bnxt/bnxt.h'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'f6974b4c2d8e1062b5a52228ee47293c15b4ee1e', 'lessThan': 'bb72b1c6755631c74b7e0878ee55bb81c06776c0', 'versionType': 'git'}, {'status': 'affected', 'version': 'f6974b4c2d8e1062b5a52228ee47293c15b4ee1e', 'lessThan': 'e26657fe3b85c068b01f42bb0c602f242d643ba9', 'versionType': 'git'}, {'status': 'affected', 'version': 'e9f11bfc03fb0d3c86f91b8ae945bb10f7e19c16', 'versionType': 'git'}, {'status': 'affected', 'version': 'ae0e135dc900827687ecc684c2bbb57aae48d318', 'versionType': 'git'}, {'status': 'affected', 'version': '6.1.45', 'lessThan': '6.2', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.4.10', 'lessThan': '6.5', 'versionType': 'semver'}], 'programFiles': ['drivers/net/ethernet/broadcom/bnxt/bnxt.c', 'drivers/net/ethernet/broadcom/bnxt/bnxt.h'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.5'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.5', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/net/ethernet/broadcom/bnxt/bnxt.c', 'drivers/net/ethernet/broadcom/bnxt/bnxt.h'], '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': 'f6974b4c2d8e1062b5a52228ee47293c15b4ee1e', 'lessThan': 'bb72b1c6755631c74b7e0878ee55bb81c06776c0', 'versionType': 'git'}, {'status': 'affected', 'version': 'f6974b4c2d8e1062b5a52228ee47293c15b4ee1e', 'lessThan': 'e26657fe3b85c068b01f42bb0c602f242d643ba9', 'versionType': 'git'}, {'status': 'affected', 'version': 'e9f11bfc03fb0d3c86f91b8ae945bb10f7e19c16', 'versionType': 'git'}, {'status': 'affected', 'version': 'ae0e135dc900827687ecc684c2bbb57aae48d318', 'versionType': 'git'}, {'status': 'affected', 'version': '6.1.45', 'lessThan': '6.2', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.4.10', 'lessThan': '6.5', 'versionType': 'semver'}], 'programFiles': ['drivers/net/ethernet/broadcom/bnxt/bnxt.c', 'drivers/net/ethernet/broadcom/bnxt/bnxt.h'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.5'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.5', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/net/ethernet/broadcom/bnxt/bnxt.c', 'drivers/net/ethernet/broadcom/bnxt/bnxt.h'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: bnxt: fix head underflow on XDP head-grow The xdp.py test test_xdp_native_adjst_head_grow_data crashes when run on a bnxt machine (and also crashes in NIPA). It seems that the bug is an underflow in bnxt_rx_multi_page_skb, which builds the skb head: napi_build_skb(data_ptr - bp->rx_offset, rxr->rx_page_size); The problem with this expression is that in page mode, rx_offset is: bp->rx_offset = NET_IP_ALIGN + XDP_PACKET_HEADROOM; Which evaluates (at least on x86_64) to 258. The test test_xdp_native_adjst_head_grow_data tests a case where the head is adjusted by -256. When this test runs, data_ptr is shifted to frag_start + 2 (where frag_start = page_address(page) + offset). Then, bnxt_rx_multi_page_skb is invoked and the napi_build_skb expression subtracts 258, landing at an address before frag_start. This could be either the previous fragment or the previous physical page when the offset is < 256 (e.g. if the fragment started at offset 0). When the skb is freed, the page pool fragment reference is dropped on either the wrong page or the wrong frag of the right page. In either case, the corrupted reference count can lead to the page being prematurely recycled while still in use. Once (incorrectly) recycled, it can be handed out again and on driver teardown this would result in a double free. The commit under fixes updated this code to handle the case where the native page size is >= 64k, but it unintentionally broke the head grow case. To fix this, add an offset field to struct bnxt_sw_rx_bd, mirroring the existing offset field in struct bnxt_sw_rx_agg_bd. Populate it on allocation and preserve it on reuse. In bnxt_rx_multi_page_skb, use the newly added offset field to compute the fragment start and pass that to napi_build_skb. Adjust the layout with skb_reserve. There are two cases, the non-adjustment case and the adjustment case. In both cases, the skb is built at page_address(page) + offset to account for the case where the native page size >= 64K and skb_reserve is called with data_ptr - (page_address(page) + offset). That difference equals bp->rx_offset when data_ptr was not moved, or bp->rx_offset + xdp_adjust when XDP adjusted the head. Re-running the failing test with this commit applied causes the test to run successfully to completion. The other rx_skb_func implementations don't have this issue. Added Reference https://git.kernel.org/stable/c/bb72b1c6755631c74b7e0878ee55bb81c06776c0 Added Reference https://git.kernel.org/stable/c/e26657fe3b85c068b01f42bb0c602f242d643ba9