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NVD / CVE Program· CNA Linux

CVE-2026-46099: net: ipv6: fix NOREF dst use in seg6 and rpl lwtunnels

Noroxi assessment

Priority: Monitor (action score 32/100)

  • 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: 0.28% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: Linux Linux 51fef5a7c4d160839199e941929456ba21ddf73c, 52f9db67f8f35f436366cf4980b4f0a2583d0ef0, 6bd17925bd6866027a6555db17905b9fc073d38d; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 51fef5a7c4d160839199e941929456ba21ddf73c, 52f9db67f8f35f436366cf4980b4f0a2583d0ef0, 6bd17925bd6866027a6555db17905b9fc073d38d; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1 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: net: ipv6: fix NOREF dst use in seg6 and rpl lwtunnels seg6_input_core() and rpl_input() call ip6_route_input() which sets a NOREF dst on the skb, then pass it to dst_cache_set_ip6() invoking dst_hold() unconditionally. On PREEMPT_RT, ksoftirqd is preemptible and a higher-priority task can release the underlying pcpu_rt between the lookup and the caching through a concurrent FIB lookup on a shared nexthop. Simplified race sequence: ksoftirqd/X higher-prio task (same CPU X) ----------- -------------------------------- seg6_input_core(,skb)/rpl_input(skb) dst_cache_get() -> miss ip6_route_input(skb) -> ip6_pol_route(,skb,flags) [RT6_LOOKUP_F_DST_NOREF in flags] -> FIB lookup resolves fib6_nh [nhid=N route] -> rt6_make_pcpu_route() [creates pcpu_rt, refcount=1] pcpu_rt->sernum = fib6_sernum [fib6_sernum=W] -> cmpxchg(fib6_nh.rt6i_pcpu, NULL, pcpu_rt) [slot was empty, store succeeds] -> skb_dst_set_noref(skb, dst) [dst is pcpu_rt, refcount still 1] rt_genid_bump_ipv6() -> bumps fib6_sernum [fib6_sernum from W to Z] ip6_route_output() -> ip6_pol_route() -> FIB lookup resolves fib6_nh [nhid=N] -> rt6_get_pcpu_route() pcpu_rt->sernum != fib6_sernum [W <> Z, stale] -> prev = xchg(rt6i_pcpu, NULL) -> dst_release(prev) [prev is pcpu_rt, refcount 1->0, dead] dst = skb_dst(skb) [dst is the dead pcpu_rt] dst_cache_set_ip6(dst) -> dst_hold() on dead dst -> WARN / use-after-free For the race to occur, ksoftirqd must be preemptible (PREEMPT_RT without PREEMPT_RT_NEEDS_BH_LOCK) and a concurrent task must be able to release the pcpu_rt. Shared nexthop objects provide such a path, as two routes pointing to the same nhid share the same fib6_nh and its rt6i_pcpu entry. Fix seg6_input_core() and rpl_input() by calling skb_dst_force() after ip6_route_input() to force the NOREF dst into a refcounted one before caching. The output path is not affected as ip6_route_output() already returns a refcounted dst.

HighCVSS 8.1 · v3.1—No exploit Fix available
Published
May 27, 2026
Updated
Oct 19, 2026
EPSS
0.2% · 21th percentile

Report tools

JSON

Action score

32

Monitor

Low priority for now.

CVSS
32 / 40 · 8.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
8.1
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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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.

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 kernel4.12 and later · before 5.15.209
  • linux linux kernel5.16 and later · before 6.1.175
  • linux linux kernel6.2 and later · before 6.6.140
  • linux linux kernel6.7 and later · before 6.12.86
  • linux linux kernel6.13 and later · before 6.18.27
  • linux linux kernel6.19 and later · before 7.0.4
  • linux linux kernel7.1

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

    • 4.12affected
    • af4a2209b1344939eaac11f269c261d347cbc3ee and later · before 51fef5a7c4d160839199e941929456ba21ddf73caffected · git
    • af4a2209b1344939eaac11f269c261d347cbc3ee and later · before b258b849a580285a1692e782ebc902b44c884a71affected · git
    • af4a2209b1344939eaac11f269c261d347cbc3ee and later · before 6bd17925bd6866027a6555db17905b9fc073d38daffected · git
    • af4a2209b1344939eaac11f269c261d347cbc3ee and later · before 52f9db67f8f35f436366cf4980b4f0a2583d0ef0affected · git
    • af4a2209b1344939eaac11f269c261d347cbc3ee and later · before b778b6d095421619c331fd2d7751143cd5387103affected · git
    • af4a2209b1344939eaac11f269c261d347cbc3ee and later · before 9dd5481f960e337b81d7dfe429529495c1c481c0affected · git
    • af4a2209b1344939eaac11f269c261d347cbc3ee and later · before f9c52a6ba9780bd27e0bf4c044fd91c13c778b6eaffected · git
    • before 4.12not affected · semver
    • 5.15.209 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 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.39.1.el10_26.12.0-211.39.1.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-2026-46090May 27, 2026 · ALSA: aloop: Fix peer runtime UAF during format-change stop
    31Monitor
  • ← EarlierCVE-2026-46092May 27, 2026 · wifi: rtw88: check for PCI upstream bridge existence
    22Monitor
  • Later →CVE-2026-46101May 27, 2026 · netfilter: reject zero shift in nft_bitwise
    22Monitor

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 Linux51fef5a7c4d160839199e941929456ba21ddf73cVendor (CNA)
Linux Linux52f9db67f8f35f436366cf4980b4f0a2583d0ef0Vendor (CNA)
Linux Linux6bd17925bd6866027a6555db17905b9fc073d38dVendor (CNA)
Linux Linux9dd5481f960e337b81d7dfe429529495c1c481c0Vendor (CNA)
Linux Linuxb258b849a580285a1692e782ebc902b44c884a71Vendor (CNA)
Linux Linuxb778b6d095421619c331fd2d7751143cd5387103Vendor (CNA)
Linux Linuxf9c52a6ba9780bd27e0bf4c044fd91c13c778b6eVendor (CNA)
azl3 kernel 6.6.139.1-1 on Azure Linux 3.06.6.141.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:kernel5.14.0-687.29.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k5.14.0-687.29.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-core5.14.0-687.29.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug5.14.0-687.29.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-core5.14.0-687.29.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel5.14.0-687.29.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched5.14.0-687.29.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules5.14.0-687.29.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-core5.14.0-687.29.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra5.14.0-687.29.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel5.14.0-687.29.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel-matched5.14.0-687.29.1.el9_8 · AlmaLinux:9Package registry (OSV)
debian:linux6.1.176-1 · Debian:12Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel-matched0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debuginfo0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel-matched0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-debuginfo0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel-matched0:6.12.0-211.39.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)

+4

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

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.
  • Special conditions such as timing or configuration are required.

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
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&dev->lock);

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 (16 more)

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

All records