CVE Intelligence
Critical

CVE-2026-74269 — bnxt: fix head underflow on XDP head-grow

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.

Published Aug 15, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • Technical severity (critical)+10

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
—
No EPSS score.
Affects
Linux
Linux
CVSS base
9.8
Critical · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ f6974b4c2d8e1062b5a52228ee47293c15b4ee1e and < 4c03275bc4435cc8e25f7f3f08aff58c0e783d8d≥ f6974b4c2d8e1062b5a52228ee47293c15b4ee1e and < bb72b1c6755631c74b7e0878ee55bb81c06776c0≥ f6974b4c2d8e1062b5a52228ee47293c15b4ee1e and < e26657fe3b85c068b01f42bb0c602f242d643ba9version e9f11bfc03fb0d3c86f91b8ae945bb10f7e19c16version ae0e135dc900827687ecc684c2bbb57aae48d318≥ 6.1.45 and < 6.2≥ 6.4.10 and < 6.5version 6.5 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
9.8 CVSS 3.1 Critical 3.9 5.9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
9.8 CVSS 3.1 Critical — — Linux via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · linux/linux
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 15, 2026
  • CVSS changed · 9.8
    Oct 15, 2026 · NIST National Vulnerability Database
  • Source status changed · → Received
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Aug 15, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

3 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-99999 ipv4: validate checksum_start before completing checksum 13h
  • CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 13h
  • CVE-2026-98431 RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency 1d
  • CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
  • CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
  • CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No FIRST EPSS score.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-74269 is "bnxt: fix head underflow on XDP head-grow", rated Critical. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.8 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.

Sign in or create an account to comment and suggest corrections.