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Linux KernelOperating system · Linux

CVE-2026-53091

HIGH · 8.4 CVSS v3.1 Published 2026-06-24
Fix available
A fix is available. Upgrade to 7.0.10 or later.
See remediation →
86/100
Remediation priority · High
Zero-click Patch available 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: net: pull headers in qdisc_pkt_len_segs_init() Most ndo_start_xmit() methods expects headers of gso packets to be already in skb->head. net/core/tso.c users are particularly at risk, because tso_build_hdr() does a memcpy(hdr, skb->data, hdr_len); qdisc_pkt_len_segs_init() already does a dissection of gso packets. Use pskb_may_pull() instead of skb_header_pointer() to make sure drivers do not have to reimplement this. Some malicious packets could be fed, detect them so that we can drop them sooner with a new SKB_DROP_REASON_SKB_BAD_GSO drop_reason.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Linux kernel's qdisc_pkt_len_segs_init() function fails to properly pull GSO (Generic Segmentation Offload) packet headers into skb->head before processing. This causes drivers expecting headers in skb->head (particularly TSO users in net/core/tso.c) to perform unsafe memory operations via memcpy() from skb->data, potentially leading to memory corruption or information disclosure. The fix adds pskb_may_pull() to ensure headers are pulled and introduces a new SKB_DROP_REASON_SKB_BAD_GSO drop reason for detecting malformed GSO packets.

MitigationApply the kernel update containing this fix; ensure network drivers receive GSO packets with properly pulled headers. Monitor for the new SKB_DROP_REASON_SKB_BAD_GSO drop reason to detect exploitation attempts.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 3.16, < 7.0.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check kernel version for vulnerability range
    Run `uname -r` or `cat /proc/version` to obtain the running kernel version. Compare against the kernel version that includes the fix (the patch replaces skb_header_pointer() with pskb_may_pull() in qdisc_pkt_len_segs_init).
    Affected if The kernel version is older than the version containing the security fix.
  2. Verify GSO support is enabled
    Check if Generic Segmentation Offload is enabled by running `ethtool -k <interface>` or looking for 'generic-segmentation-offload' in the output. Also check kernel config with `grep -i gso /boot/config-$(uname -r)` or `zcat /proc/config.gz 2>/dev/null | grep -i gso`.
    Affected if GSO is enabled on any active network interface and the kernel version is vulnerable.
  3. Inspect qdisc_pkt_len_segs_init function
    Examine the kernel source or module for the qdisc_pkt_len_segs_init function. Search for the presence of skb_header_pointer() calls within this function that have not been replaced with pskb_may_pull(). On live systems, this may require checking the vmlinux or kernel headers.
    Affected if The function still uses skb_header_pointer() without proper header pulling, indicating the vulnerability is present.
  4. Check for SKB_DROP_REASON_SKB_BAD_GSO support
    Look for the presence of SKB_DROP_REASON_SKB_BAD_GSO in the kernel source or check kernel logs for this drop reason. Search in /usr/include/linux/skbuff.h or use `grep -r 'SKB_DROP_REASON_SKB_BAD_GSO' /lib/modules/$(uname -r)/build/` if headers are available.
    Affected if The kernel lacks SKB_DROP_REASON_SKB_BAD_GSO support, suggesting the fix has not been applied.

A user is affected if running a kernel version lacking the fix (skb_header_pointer replaced with pskb_may_pull in qdisc_pkt_len_segs_init) with GSO enabled on their network interfaces.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 7.0.10 or later
Fixed in 7.0.10
Vendor patch git.kernel.org →
Interim mitigation

Apply the kernel update containing this fix; ensure network drivers receive GSO packets with properly pulled headers. Monitor for the new SKB_DROP_REASON_SKB_BAD_GSO drop reason to detect exploitation attempts.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
9.0 hours of engineering $1,570
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-53091 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data