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NVD / CVE Program· CNA Linux

CVE-2026-31413: bpf: Fix unsound scalar forking in maybe_fork_scalars() for BPF_OR

Noroxi assessment

Priority: Monitor (action score 31/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.22% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 342aa1ee995ef5bbf876096dc3a5e51218d76fa4, 58bd87d0e69204dbd739e4387a1edb0c4b1644e7, 6.12.80.

Low priority for now. Upgrade to Linux Linux 342aa1ee995ef5bbf876096dc3a5e51218d76fa4, 58bd87d0e69204dbd739e4387a1edb0c4b1644e7, 6.12.80 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: bpf: Fix unsound scalar forking in maybe_fork_scalars() for BPF_OR maybe_fork_scalars() is called for both BPF_AND and BPF_OR when the source operand is a constant. When dst has signed range [-1, 0], it forks the verifier state: the pushed path gets dst = 0, the current path gets dst = -1. For BPF_AND this is correct: 0 & K == 0. For BPF_OR this is wrong: 0 | K == K, not 0. The pushed path therefore tracks dst as 0 when the runtime value is K, producing an exploitable verifier/runtime divergence that allows out-of-bounds map access. Fix this by passing env->insn_idx (instead of env->insn_idx + 1) to push_stack(), so the pushed path re-executes the ALU instruction with dst = 0 and naturally computes the correct result for any opcode.

HighCVSS 7.8 · v3.1—Proof of concept Fix available
Published
Apr 12, 2026
Updated
Aug 5, 2026
EPSS
0.2% · 12th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CNA vs NVD score

NVD
—
CNA · Linux
7.8
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
  • Proof of concept exists, no weaponized module
  • A fix has been released

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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

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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 kernel6.12.75 and later · before 6.12.80
  • linux linux kernel6.18.16 and later · before 6.18.21
  • linux linux kernel6.19.6 and later · before 6.19.11

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

    • dea9989a3f3961faede93752cd81eb5a9514d911 and later · before 342aa1ee995ef5bbf876096dc3a5e51218d76fa4affected · git
    • 4c122e8ae14950cf6b59d208fc5160f7c601e746 and later · before 58bd87d0e69204dbd739e4387a1edb0c4b1644e7affected · git
    • e52567173ba86dbffb990595fbe60e2e83899372 and later · before d13281ae7ea8902b21d99d10a2c8caf0bdec0455affected · git
    • bffacdb80b93b7b5e96b26fad64cc490a6c7d6c7 and later · before c845894ebd6fb43226b3118d6b017942550910c5affected · git
    • 6.12.75 and later · before 6.12.80affected · semver
    • 6.18.16 and later · before 6.18.21affected · semver
    • 6.19.6 and later · before 6.19.11affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:14linuxbefore 6.19.11-16.19.11-1

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-2026-39860Apr 8, 2026 · Nix sandbox escape: file write via symlink at FOD `.tmp` copy destination
    33Monitor
  • ← EarlierCVE-2026-31412Apr 10, 2026 · usb: gadget: f_mass_storage: Fix potential integer overflow in check_command_size_in_blocks()
    22Monitor
  • Later →CVE-2026-31420Apr 13, 2026 · bridge: mrp: reject zero test interval to avoid OOM panic
    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 Linux342aa1ee995ef5bbf876096dc3a5e51218d76fa4Vendor (CNA)
Linux Linux58bd87d0e69204dbd739e4387a1edb0c4b1644e7Vendor (CNA)
Linux Linux6.12.80Vendor (CNA)
Linux Linux6.18.21Vendor (CNA)
Linux Linux6.19.11Vendor (CNA)
Linux Linuxc845894ebd6fb43226b3118d6b017942550910c5Vendor (CNA)
Linux Linuxd13281ae7ea8902b21d99d10a2c8caf0bdec0455Vendor (CNA)
debian:linux6.19.11-1 · Debian:14Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:12026-04-12

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.

  1. First PoCsame day
  2. Published
  3. TodayNov 8, 2026+211 d

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).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • 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
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/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.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (3 more)

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

All records