CVE-2026-46300
net: skbuff: preserve shared-frag marker during coalescing
Linux·Kernel
- Added
- Oct 28, 2026
- Fix due
- Oct 31, 2026
- Ransomware
- Not known
- Published
- May 23, 2026
- Updated
- Oct 29, 2026
- First covered
- Jun 29, 2026
- Latest story
- 5 months ago
Summary
In the Linux kernel, the following vulnerability has been resolved:net: skbuff: preserve shared-frag marker during coalescingskb_try_coalesce() can attach paged frags from @from to @to. If @from has SKBFL_SHARED_FRAG set, the resulting @to skb can contain the same externally-owned or page-cache-backed frags, but the shared-frag marker is currently lost.That breaks the invariant relied on by later in-place writers. In particular, ESP input checks skb_has_shared_frag() before deciding whether an uncloned nonlinear skb can skip skb_cow_data(). If TCP receive coalescing has moved shared frags into an unmarked skb, ESP can see skb_has_shared_frag() as false and decrypt in place over page-cache backed frags.Propagate SKBFL_SHARED_FRAG when skb_try_coalesce() transfers paged frags. The tailroom copy path does not need the marker because it copies bytes into @to's linear data rather than transferring frag descriptors.
CWE-123Write-what-where Condition
Attack profile
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCISA required action
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.
Affected products
- Linuxcef401de7be8c4e155c6746bfccf721a4fa5fab9 to before 3599e6b3cc1ada96883d496a50a210d3afbb6987cef401de7be8c4e155c6746bfccf721a4fa5fab9 to before 2f2b16022a2e10ca7bccfb98db5ed2ec0f72641ccef401de7be8c4e155c6746bfccf721a4fa5fab9 to before 9d3e5fd19fe1063bf607219e8562fbd567b8e8d5cef401de7be8c4e155c6746bfccf721a4fa5fab9 to before 78bf6b6bb19541d19fbda6242e7cfe2c682763c0
- Linux3.9