Out-of-bounds Write Affecting kernel-modules-extra package, versions <0:4.18.0-553.132.1.el8_10


Severity

Recommended
critical

Based on Rocky Linux security rating.

Threat Intelligence

EPSS
0.1% (27th percentile)

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  • Snyk IDSNYK-ROCKY8-KERNELMODULESEXTRA-17331840
  • published13 Jun 2026
  • disclosed1 May 2026

Introduced: 1 May 2026

CVE-2026-43037  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade Rocky-Linux:8 kernel-modules-extra to version 0:4.18.0-553.132.1.el8_10 or higher.
This issue was patched in RLSA-2026:25121.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-modules-extra package and not the kernel-modules-extra package as distributed by Rocky-Linux. See How to fix? for Rocky-Linux:8 relevant fixed versions and status.

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

ip6_tunnel: clear skb2->cb[] in ip4ip6_err()

Oskar Kjos reported the following problem.

ip4ip6_err() calls icmp_send() on a cloned skb whose cb[] was written by the IPv6 receive path as struct inet6_skb_parm. icmp_send() passes IPCB(skb2) to __ip_options_echo(), which interprets that cb[] region as struct inet_skb_parm (IPv4). The layouts differ: inet6_skb_parm.nhoff at offset 14 overlaps inet_skb_parm.opt.rr, producing a non-zero rr value. __ip_options_echo() then reads optlen from attacker-controlled packet data at sptr[rr+1] and copies that many bytes into dopt->__data, a fixed 40-byte stack buffer (IP_OPTIONS_DATA_FIXED_SIZE).

To fix this we clear skb2->cb[], as suggested by Oskar Kjos.

Also add minimal IPv4 header validation (version == 4, ihl >= 5).

CVSS Base Scores

version 3.1