Skip to content
Noroxi
CVE-2025-40046· NVD / CVE Program· CNA Linux

io_uring/zcrx: fix overshooting recv limit

In the Linux kernel, the following vulnerability has been resolved: io_uring/zcrx: fix overshooting recv limit It's reported that sometimes a zcrx request can receive more than was requested. It's caused by io_zcrx_recv_skb() adjusting desc->count for all received buffers including frag lists, but then doing recursive calls to process frag list skbs, which leads to desc->count double accounting and underflow.

HighCVSS 8.6 · v3.1—No exploit Fix available
Published
Oct 28, 2025
Updated
Aug 5, 2026
EPSS
0.3% · 26th percentile
CWE
—
Follow this CVE

Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.

Report tools

JSON

Action score

34

Monitor

Low priority for now.

CVSS
34 / 40 · 8.6 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CNA vs NVD score

NVD
—
CNA · Linux
8.6
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.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Affected systems

—

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

    • 6.15affected
    • 6699ec9a23f85f1764183430209c741847c45f12 and later · before 8bcc9eaf1b19f1a7029cba19f6bd4122b40f6c4faffected · git
    • 6699ec9a23f85f1764183430209c741847c45f12 and later · before 09cfd3c52ea76f43b3cb15e570aeddf633d65e80affected · git
    • before 6.15not 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: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
  • CVE-2026-74309vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler
    40Plan
  • CVE-2026-74280crypto: marvell/octeontx - fix DMA cleanup using wrong loop index
    40Plan
  • CVE-2026-74279crypto: cavium/cpt - fix DMA cleanup using wrong loop index
    40Plan

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 Linux09cfd3c52ea76f43b3cb15e570aeddf633d65e80Vendor (CNA)
Linux Linux8bcc9eaf1b19f1a7029cba19f6bd4122b40f6c4fVendor (CNA)
debian:linux6.17.6-1 · Debian:14Package 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.

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

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
Low
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

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

All records