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NVD / CVE Program· CNA Linux

CVE-2026-80839: batman-adv: reject unrepresentable multicast TVLV offsets

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.16% (FIRST EPSS).
  • Fixed version: Linux Linux 1b466746fe109127fd983100a228cdd1f1f6ece2, 2b46baa591d0a7c16b62f150917187e70d053be6, 916ec741e65af072b98e475feaad98c063da1b7c.

Low priority for now. Upgrade to Linux Linux 1b466746fe109127fd983100a228cdd1f1f6ece2, 2b46baa591d0a7c16b62f150917187e70d053be6, 916ec741e65af072b98e475feaad98c063da1b7c or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: batman-adv: reject unrepresentable multicast TVLV offsets The network and transport header fields in struct sk_buff are 16-bit offsets from skb->head, and U16_MAX is reserved as the unset transport header value. batadv_tvlv_call_handler() sets both fields from a received multicast TVLV without checking whether the TVLV end is representable. If the end offset exceeds the field's range, skb_set_transport_header() truncates it so that the transport header precedes the network header. The negative difference is then returned by skb_network_header_len() as a large u32. batadv_mcast_forw_packet() consequently accepts an oversized multicast tracker and accesses memory beyond the skb data. Add skb_set_transport_header_careful(), an offset-aware counterpart to skb_reset_transport_header_careful(), which validates the final head-relative offset before assigning it. Use the new helper in batadv_tvlv_call_handler() and reject unrepresentable TVLVs before setting the network header.

—No exploit Fix available
Published
Sep 4, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 6th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 6.8affected
    • 07afe1ba288c04280622fa002ed385f1ac0b6fe6 and later · before da1f5aa7ec93f2cc17f5cd30efc54f62af433cf2affected · git
    • 07afe1ba288c04280622fa002ed385f1ac0b6fe6 and later · before 916ec741e65af072b98e475feaad98c063da1b7caffected · git
    • 07afe1ba288c04280622fa002ed385f1ac0b6fe6 and later · before 1b466746fe109127fd983100a228cdd1f1f6ece2affected · git
    • 07afe1ba288c04280622fa002ed385f1ac0b6fe6 and later · before 2b46baa591d0a7c16b62f150917187e70d053be6affected · git
    • 07afe1ba288c04280622fa002ed385f1ac0b6fe6 and later · before f12c2de4f542e3220e17e0606f492110064f04cbaffected · git
    • before 6.8not affected · semver
    • 6.12.108 and later · up to and including 6.12.*not affected · semver
    • 6.18.49 and later · up to and including 6.18.*not affected · semver
    • 7.1.13 and later · up to and including 7.1.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.1.13-17.1.13-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-80837Sep 4, 2026 · netfilter: nf_tables: don't queue packet path object notifications
    0Monitor
  • ← EarlierCVE-2026-80838Sep 4, 2026 · vxlan: keep the last remote linked during FDB flush
    0Monitor
  • Later →CVE-2026-80840Sep 4, 2026 · ipv6: seg6: clear IPv4 control block on IPIP decapsulation
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux1b466746fe109127fd983100a228cdd1f1f6ece2Vendor (CNA)
Linux Linux2b46baa591d0a7c16b62f150917187e70d053be6Vendor (CNA)
Linux Linux916ec741e65af072b98e475feaad98c063da1b7cVendor (CNA)
Linux Linuxda1f5aa7ec93f2cc17f5cd30efc54f62af433cf2Vendor (CNA)
Linux Linuxf12c2de4f542e3220e17e0606f492110064f04cbVendor (CNA)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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