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

ipvs: clear IPv4 options after rebasing tunnel ICMP errors

ip_vs_in_icmp() rebases an skb from the outer ICMP packet to the
quoted original request before passing it to icmp_send(). However,
IPCB(skb)->opt still describes the outer IPv4 header.

A timestamp option in the outer header can therefore leave an offset
that points into the quoted transport header after the rebase.
__ip_options_echo() treats a byte at that stale location as the option
length and copies it into the fixed-size option storage on the
__icmp_send() stack, causing a stack out-of-bounds write.

Clear the stale option metadata after resetting the network header.
Keep the remaining control block fields, including the ingress
interface used by the ICMP response path.
Published: 2026-08-22
Score: 9.8 Critical
EPSS: < 1% Very Low
KEV: No
Impact: Stack-based Buffer Overflow in Kernel
Action: Apply Patch
AI Analysis

Impact

The flaw resides in the ipvs implementation of the Linux kernel. When an ICMP error packet is rebased to the original request packet, the skb's network header is reset but the IPv4 option metadata in the control block is not cleared. A timestamp option in the stale outer header can then persist, and the __ip_options_echo routine interprets data at that offset as an option length, copying it into a fixed‑size buffer on the stack and producing an out‑of‑bounds write. This stack corruption allows an attacker to execute arbitrary code at kernel mode, a classic buffer overflow (CWE‑787).

Affected Systems

Any Linux kernel that contains the ipvs module and has not yet incorporated the recent patch is affected. The vulnerability is present in the default ipvs implementation shipped with the kernel, regardless of distribution. Specific version ranges are not listed, so all builds that have included the unpatched ipvs code are vulnerable until a kernel version containing the fix is deployed.

Risk and Exploitability

The CVSS score of 9.8 indicates a critical impact, while the EPSS score of less than 1 % suggests a low probability of real‑world exploitation at present. The vulnerability is not listed in the CISA KEV catalog. Exploitation would require an attacker to craft a malformed ICMP error packet that triggers the rebase path in ipvs. The stack out‑of‑bounds write can lead to arbitrary code execution in kernel mode, providing an attacker with full control over the affected host. In practice, the attack vector is inferred to involve sending such a packet from a remote host through the network.

Generated by OpenCVE AI on August 25, 2026 at 07:43 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade the Linux kernel to a version that contains the ipvs option‑clearing patch, such as the latest stable release.
  • Reboot the system to load the updated kernel and ensure all kernel modules are compiled against the new code.
  • If IPVS functionality is not required, disable or remove the ipvs module to eliminate the vulnerable code path.
  • For custom or embedded kernels, recompile any IPVS modules against the patched kernel sources.

Generated by OpenCVE AI on August 25, 2026 at 07:43 UTC.

Tracking

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4777-1 linux security update
Debian DSA Debian DSA DSA-6466-1 linux security update
History

Tue, 25 Aug 2026 06:00:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}


Mon, 24 Aug 2026 14:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-119

Mon, 24 Aug 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-787
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Important


Sat, 22 Aug 2026 19:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-119

Sat, 22 Aug 2026 15:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ipvs: clear IPv4 options after rebasing tunnel ICMP errors ip_vs_in_icmp() rebases an skb from the outer ICMP packet to the quoted original request before passing it to icmp_send(). However, IPCB(skb)->opt still describes the outer IPv4 header. A timestamp option in the outer header can therefore leave an offset that points into the quoted transport header after the rebase. __ip_options_echo() treats a byte at that stale location as the option length and copies it into the fixed-size option storage on the __icmp_send() stack, causing a stack out-of-bounds write. Clear the stale option metadata after resetting the network header. Keep the remaining control block fields, including the ingress interface used by the ICMP response path.
Title ipvs: clear IPv4 options after rebasing tunnel ICMP errors
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-25T05:41:24.114Z

Reserved: 2026-08-15T05:44:03.924Z

Link: CVE-2026-74669

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-22T16:16:40.827

Modified: 2026-08-25T06:18:49.053

Link: CVE-2026-74669

cve-icon Redhat

Severity : Important

Publid Date: 2026-08-22T00:00:00Z

Links: CVE-2026-74669 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-25T07:45:04Z

Weaknesses