CVE Intelligence
High

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

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

Published Oct 28, 2025 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+1
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.15%
ahead of 4% of scored CVEs · Oct 14, 2026
Affects
Linux
Linux
CVSS base
7.8
High · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ 25ad10658dc1068a671553ff10e19a812c2a3783 and < 92751937f12a7d34ad492577a251c94a55e97e72≥ 25ad10658dc1068a671553ff10e19a812c2a3783 and < 918a399501e28e0cc36dbd1fcfb4208f8aa1e4d1≥ 25ad10658dc1068a671553ff10e19a812c2a3783 and < fd2e08128944a7679e753f920e9eda72057e427cversion 6.6 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.8 CVSS 3.1 High 1.8 5.9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
7.8 CVSS 3.1 High — — Linux via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.15%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · linux/linux
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • CVSS changed · 7.8
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Deferred
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • 2025
  • CVE published
    Oct 28, 2025 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

3 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-99999 ipv4: validate checksum_start before completing checksum 15h
  • CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 15h
  • CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
  • CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
  • CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
  • CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-40079 is "riscv, bpf: Sign extend struct ops return values properly", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.15% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.

Sign in or create an account to comment and suggest corrections.