How severe is CVE-2026-29645?

CVE-2026-29645 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-29645 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-29645?

CVE-2026-29645 affects Xiangshan Nemu. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-29645?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-29645 have an EU (EUVD) identifier?

Yes. CVE-2026-29645 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23937.

When was CVE-2026-29645 published?

CVE-2026-29645 was published on 2026-04-20 and last updated on 2026-06-17.

CVE-2026-29645

CVE-2026-29645 is a high-severity vulnerability in Xiangshan Nemu with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-131.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-23937
Weakness: CWE-131
Affected product: Xiangshan Nemu
Published: 2026-04-20
Last modified: 2026-06-17

Description

NEMU (OpenXiangShan/NEMU) before v2025.12.r2 contains an improper instruction-validation flaw in its RISC-V Vector (RVV) decoder. The decoder does not correctly validate the funct3 field when decoding vsetvli/vsetivli/vsetvl, allowing certain invalid OP-V instruction encodings to be misinterpreted and executed as vset* configuration instructions rather than raising an illegal-instruction exception. This can be exploited by providing crafted RISC-V binaries to cause incorrect trap behavior, architectural state corruption/divergence, and potential denial of service in systems that rely on NEMU for correct execution or sandboxing.

Frequently asked questions

What is CVE-2026-29645?: NEMU (OpenXiangShan/NEMU) before v2025.12.r2 contains an improper instruction-validation flaw in its RISC-V Vector (RVV) decoder. The decoder does not correctly validate the funct3 field when decoding vsetvli/vsetivli/vsetvl, allowing certain invalid OP-V instruction encodings to be misinterpreted and executed as vset* configuration instructions rather than raising an illegal-instruction exception. This can be exploited by providing crafted RISC-V binaries to cause incorrect trap behavior, architectural state corruption/divergence, and potential denial of service in systems that rely on NEMU for correct execution or sandboxing.
How severe is CVE-2026-29645?: CVE-2026-29645 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-29645 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-29645?: CVE-2026-29645 affects Xiangshan Nemu. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-29645?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-29645 have an EU (EUVD) identifier?: Yes. CVE-2026-29645 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23937.
When was CVE-2026-29645 published?: CVE-2026-29645 was published on 2026-04-20 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:xiangshan:nemu:2025.12:r1:*:*:*:*:*:*

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