CVE-2026-53362
ipv6: account for fraggap on the paged allocation path
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. 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. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Linux Kernel Unspecified Vulnerability.
- Added
- 27 Aug 2026
- Fix due (US federal)
- 30 Aug 2026
- Used by ransomware
- Not known
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: it is being exploited.
Timeline
ID reserved
By Linux
- 25 days later
· 25 days later
Published
- 54 days later
· 54 days later
Added to CISA KEV
Known exploited in the wild
- 49 days later
· 49 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.71% · top 46% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Weakness
Affected products
- affected 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 – < 14200d435af9a9eeb444f529fc2f689a236b7962
- affected 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 – < 65fb14cbebb0cd0eff903a22d33537ddc8b95769
- affected 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 – < 46f201f8b4c39633a1fa3dc12459f506d470993d
- affected 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 – < 6374fb9edf72c67a118a2c214a0dddd04c921e0a
- affected 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 – < e9eacf19281ea2498b36291b56c9606118c2d74e
- affected 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 – < 736b380e28d0480c7bc3e022f1950f31fe53a7c5
- affected 6.0
- unaffected < 6.0
- unaffected 6.1.177 – ≤ 6.1.*
- unaffected 6.6.144 – ≤ 6.6.*
- unaffected 6.12.95 – ≤ 6.12.*
- unaffected 6.18.38 – ≤ 6.18.*
- unaffected 7.1.3 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References (8)
- https://git.kernel.org/stable/c/14200d435af9a9eeb444f529fc2f689a236b7962 (opens in a new tab)
- https://git.kernel.org/stable/c/65fb14cbebb0cd0eff903a22d33537ddc8b95769 (opens in a new tab)
- https://git.kernel.org/stable/c/46f201f8b4c39633a1fa3dc12459f506d470993d (opens in a new tab)
- https://git.kernel.org/stable/c/6374fb9edf72c67a118a2c214a0dddd04c921e0a (opens in a new tab)
- https://git.kernel.org/stable/c/e9eacf19281ea2498b36291b56c9606118c2d74e (opens in a new tab)
- https://git.kernel.org/stable/c/736b380e28d0480c7bc3e022f1950f31fe53a7c5 (opens in a new tab)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-53362 (opens in a new tab)government-resource
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-53362)Record last updated .