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NVD / CVE Program· CNA Linux

CVE-2025-40079: riscv, bpf: Sign extend struct ops return values properly

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.15% (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 918a399501e28e0cc36dbd1fcfb4208f8aa1e4d1, 92751937f12a7d34ad492577a251c94a55e97e72, fd2e08128944a7679e753f920e9eda72057e427c.

Low priority for now. Upgrade to Linux Linux 918a399501e28e0cc36dbd1fcfb4208f8aa1e4d1, 92751937f12a7d34ad492577a251c94a55e97e72, fd2e08128944a7679e753f920e9eda72057e427c 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: riscv, bpf: Sign extend struct ops return values properly The ns_bpf_qdisc selftest triggers a kernel panic: Unable to handle kernel paging request at virtual address ffffffffa38dbf58 Current test_progs pgtable: 4K pagesize, 57-bit VAs, pgdp=0x00000001109cc000 [ffffffffa38dbf58] pgd=000000011fffd801, p4d=000000011fffd401, pud=000000011fffd001, pmd=0000000000000000 Oops [#1] Modules linked in: bpf_testmod(OE) xt_conntrack nls_iso8859_1 [...] [last unloaded: bpf_testmod(OE)] CPU: 1 UID: 0 PID: 23584 Comm: test_progs Tainted: G W OE 6.17.0-rc1-g2465bb83e0b4 #1 NONE Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Hardware name: Unknown Unknown Product/Unknown Product, BIOS 2024.01+dfsg-1ubuntu5.1 01/01/2024 epc : __qdisc_run+0x82/0x6f0 ra : __qdisc_run+0x6e/0x6f0 epc : ffffffff80bd5c7a ra : ffffffff80bd5c66 sp : ff2000000eecb550 gp : ffffffff82472098 tp : ff60000096895940 t0 : ffffffff8001f180 t1 : ffffffff801e1664 t2 : 0000000000000000 s0 : ff2000000eecb5d0 s1 : ff60000093a6a600 a0 : ffffffffa38dbee8 a1 : 0000000000000001 a2 : ff2000000eecb510 a3 : 0000000000000001 a4 : 0000000000000000 a5 : 0000000000000010 a6 : 0000000000000000 a7 : 0000000000735049 s2 : ffffffffa38dbee8 s3 : 0000000000000040 s4 : ff6000008bcda000 s5 : 0000000000000008 s6 : ff60000093a6a680 s7 : ff60000093a6a6f0 s8 : ff60000093a6a6ac s9 : ff60000093140000 s10: 0000000000000000 s11: ff2000000eecb9d0 t3 : 0000000000000000 t4 : 0000000000ff0000 t5 : 0000000000000000 t6 : ff60000093a6a8b6 status: 0000000200000120 badaddr: ffffffffa38dbf58 cause: 000000000000000d [<ffffffff80bd5c7a>] __qdisc_run+0x82/0x6f0 [<ffffffff80b6fe58>] __dev_queue_xmit+0x4c0/0x1128 [<ffffffff80b80ae0>] neigh_resolve_output+0xd0/0x170 [<ffffffff80d2daf6>] ip6_finish_output2+0x226/0x6c8 [<ffffffff80d31254>] ip6_finish_output+0x10c/0x2a0 [<ffffffff80d31446>] ip6_output+0x5e/0x178 [<ffffffff80d2e232>] ip6_xmit+0x29a/0x608 [<ffffffff80d6f4c6>] inet6_csk_xmit+0xe6/0x140 [<ffffffff80c985e4>] __tcp_transmit_skb+0x45c/0xaa8 [<ffffffff80c995fe>] tcp_connect+0x9ce/0xd10 [<ffffffff80d66524>] tcp_v6_connect+0x4ac/0x5e8 [<ffffffff80cc19b8>] __inet_stream_connect+0xd8/0x318 [<ffffffff80cc1c36>] inet_stream_connect+0x3e/0x68 [<ffffffff80b42b20>] __sys_connect_file+0x50/0x88 [<ffffffff80b42bee>] __sys_connect+0x96/0xc8 [<ffffffff80b42c40>] __riscv_sys_connect+0x20/0x30 [<ffffffff80e5bcae>] do_trap_ecall_u+0x256/0x378 [<ffffffff80e69af2>] handle_exception+0x14a/0x156 Code: 892a 0363 1205 489c 8bc1 c7e5 2d03 084a 2703 080a (2783) 0709 ---[ end trace 0000000000000000 ]--- The bpf_fifo_dequeue prog returns a skb which is a pointer. The pointer is treated as a 32bit value and sign extend to 64bit in epilogue. This behavior is right for most bpf prog types but wrong for struct ops which requires RISC-V ABI. So let's sign extend struct ops return values according to the function model and RISC-V ABI([0]). [0]: https://riscv.org/wp-content/uploads/2024/12/riscv-calling.pdf

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Oct 28, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 4th percentile
CWE
—

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 · 0.1%

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.

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

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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

    • 6.6affected
    • 25ad10658dc1068a671553ff10e19a812c2a3783 and later · before 92751937f12a7d34ad492577a251c94a55e97e72affected · git
    • 25ad10658dc1068a671553ff10e19a812c2a3783 and later · before 918a399501e28e0cc36dbd1fcfb4208f8aa1e4d1affected · git
    • 25ad10658dc1068a671553ff10e19a812c2a3783 and later · before fd2e08128944a7679e753f920e9eda72057e427caffected · git
    • before 6.6not affected · semver
    • 6.12.53 and later · up to and including 6.12.*not affected · semver
    • 6.17.3 and later · up to and including 6.17.*not affected · semver
    • 6.18 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:13linuxbefore 6.12.57-16.12.57-1
Debian:14linuxbefore 6.17.6-16.17.6-1

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-2025-40077Oct 28, 2025 · f2fs: fix to avoid overflow while left shift operation
    0Monitor
  • ← EarlierCVE-2025-40078Oct 28, 2025 · bpf: Explicitly check accesses to bpf_sock_addr
    0Monitor
  • Later →CVE-2025-40080Oct 28, 2025 · nbd: restrict sockets to TCP and UDP
    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 Linux918a399501e28e0cc36dbd1fcfb4208f8aa1e4d1Vendor (CNA)
Linux Linux92751937f12a7d34ad492577a251c94a55e97e72Vendor (CNA)
Linux Linuxfd2e08128944a7679e753f920e9eda72057e427cVendor (CNA)
debian:linux6.12.57-1 · Debian:13Package 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.

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)

—

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.

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 (2 more)

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

All records