Skip to content
Noroxi
NVD / CVE Program· CNA Linux

CVE-2026-43186: ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()

CriticalCVSS 9.8 · v3.1—No exploit Fix available

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: 0.64% (FIRST EPSS); higher than 51.2% 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.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 0591d6509c2ff13f09ea2998434aba0c0472e978, 632d233cf2e64a46865ae2c064ae3c9df7c8864f, 6db8b56eed62baacaf37486e83378a72635c04cc.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0591d6509c2ff13f09ea2998434aba0c0472e978, 632d233cf2e64a46865ae2c064ae3c9df7c8864f, 6db8b56eed62baacaf37486e83378a72635c04cc 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: ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data() On the receive path, __ioam6_fill_trace_data() uses trace->nodelen to decide how much data to write for each node. It trusts this field as-is from the incoming packet, with no consistency check against trace->type (the 24-bit field that tells which data items are present). A crafted packet can set nodelen=0 while setting type bits 0-21, causing the function to write ~100 bytes past the allocated region (into skb_shared_info), which corrupts adjacent heap memory and leads to a kernel panic. Add a shared helper ioam6_trace_compute_nodelen() in ioam6.c to derive the expected nodelen from the type field, and use it: - in ioam6_iptunnel.c (send path, existing validation) to replace the open-coded computation; - in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose nodelen is inconsistent with the type field, before any data is written. Per RFC 9197, bits 12-21 are each short (4-octet) fields, so they are included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to 0xff1ffc00).

Published
May 6, 2026
Updated
Nov 11, 2026
EPSS
0.6% · 51th percentile

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 · 0.6%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

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.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-43186

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Your free account also gets you

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for linux records
Is your version affected? Check it

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.

We use this product, ask for help

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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.15 and later · before 5.15.202
  • linux linux kernel5.16 and later · before 6.1.165
  • linux linux kernel6.2 and later · before 6.6.128
  • linux linux kernel6.7 and later · before 6.12.75
  • linux linux kernel6.13 and later · before 6.18.16
  • linux linux kernel6.19 and later · before 6.19.6

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

    • 5.15affected
    • 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 and later · before f4d9d4b8fd839719d564651671e24c62c545c23baffected · git
    • 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 and later · before fb3c662fafebc5b9d74417ed1de8759f6bb72143affected · git
    • 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 and later · before 632d233cf2e64a46865ae2c064ae3c9df7c8864faffected · git
    • 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 and later · before 0591d6509c2ff13f09ea2998434aba0c0472e978affected · git
    • 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 and later · before e90346a2f1e8917d5760a44a1f61c44e3b36d96baffected · git
    • 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 and later · before ea3632aefc04205436868541638e26f4a74d5637affected · git
    • 9ee11f0fff205b4b3df9750bff5e94f97c71b6a0 and later · before 6db8b56eed62baacaf37486e83378a72635c04ccaffected · git
    • before 5.15not affected · semver
    • 5.15.202 and later · up to and including 5.15.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.44.1.el10_26.12.0-211.44.1.el10_2

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-43184May 6, 2026 · rnbd-srv: Zero the rsp buffer before using it
    30Monitor
  • ← EarlierCVE-2026-43185May 6, 2026 · ksmbd: fix signededness bug in smb_direct_prepare_negotiation()
    39Monitor
  • Later →CVE-2026-43187May 6, 2026 · xfs: delete attr leaf freemap entries when empty
    35Monitor

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 Linux0591d6509c2ff13f09ea2998434aba0c0472e978Vendor (CNA)
Linux Linux632d233cf2e64a46865ae2c064ae3c9df7c8864fVendor (CNA)
Linux Linux6db8b56eed62baacaf37486e83378a72635c04ccVendor (CNA)
Linux Linuxe90346a2f1e8917d5760a44a1f61c44e3b36d96bVendor (CNA)
Linux Linuxea3632aefc04205436868541638e26f4a74d5637Vendor (CNA)
Linux Linuxf4d9d4b8fd839719d564651671e24c62c545c23bVendor (CNA)
Linux Linuxfb3c662fafebc5b9d74417ed1de8759f6bb72143Vendor (CNA)
almalinux:kernel6.12.0-211.44.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k6.12.0-211.44.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-core6.12.0-211.44.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug6.12.0-211.44.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-core6.12.0-211.44.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel6.12.0-211.44.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched6.12.0-211.44.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules6.12.0-211.44.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-core6.12.0-211.44.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra6.12.0-211.44.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel6.12.0-211.44.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel-matched6.12.0-211.44.1.el10_2 · AlmaLinux:10Package registry (OSV)
debian:linux6.1.170-1 · Debian:12Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:6.12.0-211.44.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel0:6.12.0-211.44.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel-matched0:6.12.0-211.44.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debuginfo0:6.12.0-211.44.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel0:6.12.0-211.44.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel-matched0:6.12.0-211.44.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-debuginfo0:6.12.0-211.44.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel0:6.12.0-211.44.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel-matched0:6.12.0-211.44.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debuginfo0:6.12.0-211.44.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)

+3

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.

No history yet (it accumulates with the daily EPSS job).

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

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)

CWE-787 · Out-of-bounds Write

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. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (6 more)

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

All records