NVD / CVE Program· CNA Linux

CVE-2024-35873: riscv: Fix vector state restore in rt_sigreturn()

Noroxi assessment

Priority: Monitor (action score 22/100)

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: 0.19% (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 5b16d904e910183181b9d90efa957c787a8ac91b, c27fa53b858b4ee6552a719aa599c250cf98a586.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 5b16d904e910183181b9d90efa957c787a8ac91b, c27fa53b858b4ee6552a719aa599c250cf98a586 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: Fix vector state restore in rt_sigreturn() The RISC-V Vector specification states in "Appendix D: Calling Convention for Vector State" [1] that "Executing a system call causes all caller-saved vector registers (v0-v31, vl, vtype) and vstart to become unspecified.". In the RISC-V kernel this is called "discarding the vstate". Returning from a signal handler via the rt_sigreturn() syscall, vector discard is also performed. However, this is not an issue since the vector state should be restored from the sigcontext, and therefore not care about the vector discard. The "live state" is the actual vector register in the running context, and the "vstate" is the vector state of the task. A dirty live state, means that the vstate and live state are not in synch. When vectorized user_from_copy() was introduced, an bug sneaked in at the restoration code, related to the discard of the live state. An example when this go wrong: 1. A userland application is executing vector code 2. The application receives a signal, and the signal handler is entered. 3. The application returns from the signal handler, using the rt_sigreturn() syscall. 4. The live vector state is discarded upon entering the rt_sigreturn(), and the live state is marked as "dirty", indicating that the live state need to be synchronized with the current vstate. 5. rt_sigreturn() restores the vstate, except the Vector registers, from the sigcontext 6. rt_sigreturn() restores the Vector registers, from the sigcontext, and now the vectorized user_from_copy() is used. The dirty live state from the discard is saved to the vstate, making the vstate corrupt. 7. rt_sigreturn() returns to the application, which crashes due to corrupted vstate. Note that the vectorized user_from_copy() is invoked depending on the value of CONFIG_RISCV_ISA_V_UCOPY_THRESHOLD. Default is 768, which means that vlen has to be larger than 128b for this bug to trigger. The fix is simply to mark the live state as non-dirty/clean prior performing the vstate restore.

MediumCVSS 5.5 · v3.1—No exploit Fix available

Denial of service

BDU:2026-03503

Published: May 19, 2024
Updated: Jun 17, 2026
EPSS: 0.1% · 9th percentile
CWE: —

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 22 / 40 · 5.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

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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?

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Affected systems

Is your version affected?

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Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

linux linux kernel6.8 and later · before 6.8.5
linux linux kernel6.9

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
- 6.8affected
- c2a658d419246108c9bf065ec347355de5ba8a05 and later · before 5b16d904e910183181b9d90efa957c787a8ac91baffected · git
- c2a658d419246108c9bf065ec347355de5ba8a05 and later · before c27fa53b858b4ee6552a719aa599c250cf98a586affected · git
- before 6.8not affected · semver
- 6.8.5 and later · up to and including 6.8.*not affected · semver
- 6.9 and laternot affected · original_commit_for_fix

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Debian:13	linux	before 6.8.9-1	6.8.9-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
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Published before and after this one in the same product

← EarlierCVE-2024-35871May 19, 2024 · riscv: process: Fix kernel gp leakage
28Monitor
← EarlierCVE-2024-35872May 19, 2024 · mm/secretmem: fix GUP-fast succeeding on secretmem folios
22Monitor
Later →CVE-2024-35874May 19, 2024 · aio: Fix null ptr deref in aio_complete() wakeup
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 / package	Fixed version	Source
Linux Linux	5b16d904e910183181b9d90efa957c787a8ac91b	Vendor (CNA)
Linux Linux	c27fa53b858b4ee6552a719aa599c250cf98a586	Vendor (CNA)
debian:linux	6.8.9-1 · Debian:13	Package 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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-24-0506 · May 20, 2024(Linux Kernel Güncellemesi)

All national notices →

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: none
Integrity: none
Availability: high · the service can be disrupted

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

Weakness class (CWE)

—

CVSS vector

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

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

Fix✗ → ✓Sep 28, 2026, 10:09 PM UTC

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

References

git.kernel.org/stable/c/5b16d904e910183181b9d90efa957c787a8ac91b

Show all references (1 more)

git.kernel.org/stable/c/c27fa53b858b4ee6552a719aa599c250cf98a586

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

All records