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NVD / CVE Program· CNA Linux

CVE-2026-89783: xfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full

Noroxi assessment

Priority: Monitor (action score 39/100)

  • 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: 0.71% (FIRST EPSS); higher than 53.6% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 0f679e0523ddfff3fb554336ceb874b0e51e9cd3, 48996649222e95008cdb98cd58579e3fc8e5ee06, 5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bc; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1.

Low priority for now. Upgrade to Linux Linux 0f679e0523ddfff3fb554336ceb874b0e51e9cd3, 48996649222e95008cdb98cd58579e3fc8e5ee06, 5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bc; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1 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: xfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full The depth check in xfrm6_input_addr() is off by one: if (1 + sp->len == XFRM_MAX_DEPTH) goto drop; ... sp->xvec[sp->len++] = x; xfrm_input() can leave sp->len == XFRM_MAX_DEPTH, and the transport-mode receive path re-enters IPv6 input via xfrm_trans_reinject() with that secpath preserved. If the inner packet carries a destination-options HAO option or a type-2 routing header, xfrm6_input_addr() is called with sp->len == XFRM_MAX_DEPTH; the check (1 + 6 == 6) is false, so sp->xvec[sp->len++] writes one slot past the 6-element xvec[]. The write stays within the sec_path allocation (invisible to KASAN); UBSAN_BOUNDS flags it and panics under panic_on_warn. Use "sp->len >= XFRM_MAX_DEPTH", matching xfrm_input(). This also restores one chain level the old check rejected at sp->len == 5. UBSAN: array-index-out-of-bounds in net/ipv6/xfrm6_input.c:309:10 index 6 is out of range for type 'xfrm_state *[6]'

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Sep 16, 2026
Updated
Oct 19, 2026
EPSS
0.7% · 53th percentile
CWE
—

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.7%

CNA vs NVD score

NVD
—
CNA · Linux
9.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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

    • 2.6.25affected
    • 9473e1f631de339c50bde1e3bd09e1045fe90fd5 and later · before 91fc387f63c00ddfb5221127a17bac97549a8343affected · git
    • 9473e1f631de339c50bde1e3bd09e1045fe90fd5 and later · before 68e8737fe8e72f085c608cff322b3d2de8340af1affected · git
    • 9473e1f631de339c50bde1e3bd09e1045fe90fd5 and later · before 8fe2c53fb81f5ad5be43af2ad09583f7c78b4b77affected · git
    • 9473e1f631de339c50bde1e3bd09e1045fe90fd5 and later · before bdcda866c89f9a8b1acdabf02d26cde9fbe501d8affected · git
    • 9473e1f631de339c50bde1e3bd09e1045fe90fd5 and later · before 48996649222e95008cdb98cd58579e3fc8e5ee06affected · git
    • 9473e1f631de339c50bde1e3bd09e1045fe90fd5 and later · before 0f679e0523ddfff3fb554336ceb874b0e51e9cd3affected · git
    • 9473e1f631de339c50bde1e3bd09e1045fe90fd5 and later · before 5f35a29a5eed3d80befd32050843ac88dea3d61aaffected · git
    • 9473e1f631de339c50bde1e3bd09e1045fe90fd5 and later · before 5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bcaffected · git
    • before 2.6.25not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

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-2026-89781Sep 16, 2026 · fs/ntfs3: fix out-of-bounds read in read_log_rec_buf()
    33Monitor
  • ← EarlierCVE-2026-89782Sep 16, 2026 · fs/ntfs3: reject restart table growth beyond U16_MAX entries
    33Monitor
  • Later →CVE-2026-89784Sep 16, 2026 · SUNRPC: check rpc_sockaddr2uaddr() return value in rpcb_register_inet4/6
    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 Linux0f679e0523ddfff3fb554336ceb874b0e51e9cd3Vendor (CNA)
Linux Linux48996649222e95008cdb98cd58579e3fc8e5ee06Vendor (CNA)
Linux Linux5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bcVendor (CNA)
Linux Linux5f35a29a5eed3d80befd32050843ac88dea3d61aVendor (CNA)
Linux Linux68e8737fe8e72f085c608cff322b3d2de8340af1Vendor (CNA)
Linux Linux8fe2c53fb81f5ad5be43af2ad09583f7c78b4b77Vendor (CNA)
Linux Linux91fc387f63c00ddfb5221127a17bac97549a8343Vendor (CNA)
Linux Linuxbdcda866c89f9a8b1acdabf02d26cde9fbe501d8Vendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.0—Microsoft (MSRC)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.06.6.157.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
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+1% in 7 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

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

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.

—

Bug bounty scope

No known public program.

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

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

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✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

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

All records