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VulnerabilityPublished Updated

CVE-2026-53366: Linux kernel · ipv4: account for fraggap on the paged allocation path

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in eca856950f7cb1a221e02b99d758409f2c5cec42 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in eca856950f7cb1a221e02b99d758409f2c5cec42, ce494707a9c07f27c219ca67f3e138061f53d9b3, c04d9ece23deb9e26c19f9ca215e98b3295aa1bb +3
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 16 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 8eb77cc73977d88787b37c92831b1c242e035396, < eca856950f7cb1a221e02b99d758409f2c5cec42
Fixed in
  • eca856950f7cb1a221e02b99d758409f2c5cec42
LinuxLinuxAffected
  • ≥ 8eb77cc73977d88787b37c92831b1c242e035396, < ce494707a9c07f27c219ca67f3e138061f53d9b3
Fixed in
  • ce494707a9c07f27c219ca67f3e138061f53d9b3
LinuxLinuxAffected
  • ≥ 8eb77cc73977d88787b37c92831b1c242e035396, < c04d9ece23deb9e26c19f9ca215e98b3295aa1bb
Fixed in
  • c04d9ece23deb9e26c19f9ca215e98b3295aa1bb
LinuxLinuxAffected
  • ≥ 8eb77cc73977d88787b37c92831b1c242e035396, < a9c24eda24bd15f432e37824e6fc440977cb241c
Fixed in
  • a9c24eda24bd15f432e37824e6fc440977cb241c
LinuxLinuxAffected
  • ≥ 8eb77cc73977d88787b37c92831b1c242e035396, < 77798d7be6ef71e72fb6fc8a2901bf74ebc9706f
Fixed in
  • 77798d7be6ef71e72fb6fc8a2901bf74ebc9706f
LinuxLinuxAffected
  • ≥ 8eb77cc73977d88787b37c92831b1c242e035396, < 5c6375bced6147ec2e460ee3b653f4860d5ecdc2
Fixed in
  • 5c6375bced6147ec2e460ee3b653f4860d5ecdc2

Description

In the Linux kernel, the following vulnerability has been resolved: ipv4: account for fraggap on the paged allocation path In __ip_append_data(), when the paged-allocation branch is taken, alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap, but the fraggap bytes carried over from the previous skb are copied into the new skb's linear area at offset transhdrlen by the subsequent skb_copy_and_csum_bits(). The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic.

References

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