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CVE-2026-45839· NVD / CVE Program· CNA Linux

bpf: reject negative CO-RE accessor indices in bpf_core_parse_spec()

In the Linux kernel, the following vulnerability has been resolved: bpf: reject negative CO-RE accessor indices in bpf_core_parse_spec() CO-RE accessor strings are colon-separated indices that describe a path from a root BTF type to a target field, e.g. "0:1:2" walks through nested struct members. bpf_core_parse_spec() parses each component with sscanf("%d"), so negative values like -1 are silently accepted. The subsequent bounds checks (access_idx >= btf_vlen(t)) only guard the upper bound and always pass for negative values because C integer promotion converts the __u16 btf_vlen result to int, making the comparison (int)(-1) >= (int)(N) false for any positive N. When -1 reaches btf_member_bit_offset() it gets cast to u32 0xffffffff, producing an out-of-bounds read far past the members array. A crafted BPF program with a negative CO-RE accessor on any struct that exists in vmlinux BTF (e.g. task_struct) crashes the kernel deterministically during BPF_PROG_LOAD on any system with CONFIG_DEBUG_INFO_BTF=y (default on major distributions). The bug is reachable with CAP_BPF: BUG: unable to handle page fault for address: ffffed11818b6626 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page Oops: Oops: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 85 Comm: poc Not tainted 7.0.0-rc6 #18 PREEMPT(full) RIP: 0010:bpf_core_parse_spec (tools/lib/bpf/relo_core.c:354) RAX: 00000000ffffffff Call Trace: <TASK> bpf_core_calc_relo_insn (tools/lib/bpf/relo_core.c:1321) bpf_core_apply (kernel/bpf/btf.c:9507) check_core_relo (kernel/bpf/verifier.c:19475) bpf_check (kernel/bpf/verifier.c:26031) bpf_prog_load (kernel/bpf/syscall.c:3089) __sys_bpf (kernel/bpf/syscall.c:6228) </TASK> CO-RE accessor indices are inherently non-negative (struct member index, array element index, or enumerator index), so reject them immediately after parsing.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
May 27, 2026
Updated
Aug 27, 2026
EPSS
0.2% · 6th percentile
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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%

Noroxi analysis

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Affected systems

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 kernel5.4 and later · before 5.15.209
  • linux linux kernel5.16 and later · before 6.1.175
  • linux linux kernel6.2 and later · before 6.6.141
  • linux linux kernel6.7 and later · before 6.12.91
  • linux linux kernel6.13 and later · before 6.18.33
  • linux linux kernel6.19 and later · before 7.0.10

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

    • 5.4affected
    • ddc7c3042614e273044f698d2beab25cc3842d45 and later · before c8e49b79c4b48bd687706ff6e9c82638dc81ef80affected · git
    • ddc7c3042614e273044f698d2beab25cc3842d45 and later · before a9e777f856cd2f1efc106afc7bf21aef868509d5affected · git
    • ddc7c3042614e273044f698d2beab25cc3842d45 and later · before 669349b4612c26b3d7aacfa99d7174681bd19223affected · git
    • ddc7c3042614e273044f698d2beab25cc3842d45 and later · before 3ff85ae79e1a74baeb916b78a63d821f6d19a994affected · git
    • ddc7c3042614e273044f698d2beab25cc3842d45 and later · before 36a9012f76ba8d9189ae56a1f8bb7c87c07a1f3aaffected · git
    • ddc7c3042614e273044f698d2beab25cc3842d45 and later · before 76f2ebaf79a9ae6d0737b87f045fe769e425d78faffected · git
    • ddc7c3042614e273044f698d2beab25cc3842d45 and later · before 99dbab7b5a12d8f58d5b0aa2f7a1fe656a70f4b2affected · git
    • ddc7c3042614e273044f698d2beab25cc3842d45 and later · before 1c22483a2c4bbf747787f328392ca3e68619c4dcaffected · git
    • before 5.4not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.176-16.1.176-1
Debian:13linuxbefore 6.12.94-16.12.94-1
Debian:14linuxbefore 7.0.10-17.0.10-1
openSUSE:Tumbleweedkernel-sourcebefore 7.0.11-1.17.0.11-1.1

Same product

linux: all records

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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 Linux1c22483a2c4bbf747787f328392ca3e68619c4dcVendor (CNA)
Linux Linux36a9012f76ba8d9189ae56a1f8bb7c87c07a1f3aVendor (CNA)
Linux Linux3ff85ae79e1a74baeb916b78a63d821f6d19a994Vendor (CNA)
Linux Linux669349b4612c26b3d7aacfa99d7174681bd19223Vendor (CNA)
Linux Linux76f2ebaf79a9ae6d0737b87f045fe769e425d78fVendor (CNA)
Linux Linux99dbab7b5a12d8f58d5b0aa2f7a1fe656a70f4b2Vendor (CNA)
Linux Linuxa9e777f856cd2f1efc106afc7bf21aef868509d5Vendor (CNA)
Linux Linuxc8e49b79c4b48bd687706ff6e9c82638dc81ef80Vendor (CNA)
debian:linux6.1.176-1 · Debian:12Package registry (OSV)
opensuse:kernel-source7.0.11-1.1 · openSUSE:TumbleweedPackage 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

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.

  • CVE-2026-2324670 days apartwifi: mac80211: bounds-check link_id in ieee80211_ml_reconfiguration
    35Monitor
  • CVE-2026-458960 days apartmtd: intel-dg: Fix accessing regions before setting nregions
    31Monitor
  • CVE-2026-461221 days apartwifi: b43: enforce bounds check on firmware key index in b43_rx()
    31Monitor
  • CVE-2026-461631 days apartwifi: b43legacy: enforce bounds check on firmware key index in RX path
    31Monitor
  • CVE-2026-3172926 days apartusb: typec: ucsi: validate connector number in ucsi_notify_common()
    31Monitor
  • CVE-2026-3176426 days apartiio: imu: st_lsm6dsx: Set buffer sampling frequency for accelerometer only
    31Monitor

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-129 · Improper Validation of Array Index

CVSS vector

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

nvd-primary

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

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

All records