Incorrect Calculation of Buffer Size Affecting kernel-doc package, versions *


Severity

Recommended
0.0
high
0
10

Based on CentOS security rating.

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  • Snyk IDSNYK-CENTOS10-KERNELDOC-16791866
  • published22 May 2026
  • disclosed21 May 2026

Introduced: 21 May 2026

NewCVE-2026-43501  (opens in a new tab)
CWE-131  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 kernel-doc.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-doc package and not the kernel-doc package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

ipv6: rpl: reserve mac_len headroom when recompressed SRH grows

ipv6_rpl_srh_rcv() decompresses an RFC 6554 Source Routing Header, swaps the next segment into ipv6_hdr->daddr, recompresses, then pulls the old header and pushes the new one plus the IPv6 header back. The recompressed header can be larger than the received one when the swap reduces the common-prefix length the segments share with daddr (CmprI=0, CmprE>0, seg[0][0] != daddr[0] gives the maximum +8 bytes).

pskb_expand_head() was gated on segments_left == 0, so on earlier segments the push consumed unchecked headroom. Once skb_push() leaves fewer than skb->mac_len bytes in front of data, skb_mac_header_rebuild()'s call to:

skb_set_mac_header(skb, -skb->mac_len);

will store (data - head) - mac_len into the u16 mac_header field, which wraps to ~65530, and the following memmove() writes mac_len bytes ~64KiB past skb->head.

A single AF_INET6/SOCK_RAW/IPV6_HDRINCL packet over lo with a two segment type-3 SRH (CmprI=0, CmprE=15) reaches headroom 8 after one pass; KASAN reports a 14-byte OOB write in ipv6_rthdr_rcv.

Fix this by expanding the head whenever the remaining room is less than the push size plus mac_len, and request that much extra so the rebuilt MAC header fits afterwards.

CVSS Base Scores

version 3.1