ip6_gre: fix hardware header length for NBMA tunnels (CVE-2026-89562) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-89562

ip6_gre: fix hardware header length for NBMA tunnels

Answer in brief

CVE-2026-89562 records a Unknown severity vulnerability in ip6_gre: fix hardware header length for NBMA tunnels. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 11, 2026Updated Sep 11, 2026Source checked Sep 11, 2026First seen by HOL Sep 11, 2026Material review Sep 11, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=832ba596494b2c9eac7760259eff2d8b7dcad0ee <8bfe746afee38dd6e4348ddcd22d554789dbb9ff \|\| >=832ba596494b2c9eac7760259eff2d8b7dcad0ee <b8282668d8fa7c61b80e8e4890729031c291a16c \|\| >=832ba596494b2c9eac7760259eff2d8b7dcad0ee <565038b0092f65afe384961c0f548d605bf438b9 \|\| >=832ba596494b2c9eac7760259eff2d8b7dcad0ee <505b6d296c486ef7d1274f279d4c43a172f63224 \|\| cf3d9717a5271573fa193c4dfa0df856295d5b15 \|\| 187a6daf5db45adc807c85bbe285319107bed198 \|\| d9897bb66ce989325b4bf4cdbb6a799e4ac878b6 \|\| >=4.19.162 <4.20 \|\| >=5.4.82 <5.5 \|\| >=5.9.13 <5.10	8bfe746afee38dd6e4348ddcd22d554789dbb9ff, b8282668d8fa7c61b80e8e4890729031c291a16c, 565038b0092f65afe384961c0f548d605bf438b9, 505b6d296c486ef7d1274f279d4c43a172f63224, 4.20, 5.5, 5.10
Linux/Linuxgeneric	5.10	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 8bfe746afee38dd6e4348ddcd22d554789dbb9ff if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 11, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: ip6_gre: fix hardware header length for NBMA tunnels ip6gre_tnl_link_config_route() accumulates the lower device's hardware header length into dev->hard_header_len whenever header_ops is set. This is incorrect for both users of header_ops. ip6gretap and ip6erspan have a fixed Ethernet hardware header length. For an NBMA ip6gre tunnel, ip6gre_header() creates only the GRE header, the optional FOU or GUE header, and the outer IPv6 header. The lower device header is headroom needed later, not part of the tunnel device's hardware header. Keep the lower device header in needed_headroom. Set hard_header_len to the tunnel header length only for ARPHRD_IP6GRE devices with header_ops, and leave the fixed Ethernet header length unchanged for tap and erspan devices.

Quoted source text, attributed separately from HOL analysis.