How severe is CVE-2026-29649?

CVE-2026-29649 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-29649 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-29649?

CVE-2026-29649 affects Xiangshan Nemu. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-29649?

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

Does CVE-2026-29649 have an EU (EUVD) identifier?

Yes. CVE-2026-29649 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23944.

When was CVE-2026-29649 published?

CVE-2026-29649 was published on 2026-04-20 and last updated on 2026-06-17.

CVE-2026-29649

CVE-2026-29649 is a critical-severity vulnerability in Xiangshan Nemu with a CVSS 3.x base score of 9.8. 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-693.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 0% (36th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-23944
Weakness: CWE-693
Affected product: Xiangshan Nemu
Published: 2026-04-20
Last modified: 2026-06-17

Description

NEMU contains an implementation flaw in its RISC-V Hypervisor CSR handling where henvcfg[7:4] (CBIE/CBCFE/CBZE-related fields) is incorrectly masked/updated based on menvcfg[7:4], so a machine-mode write to menvcfg can implicitly modify the hypervisor's environment configuration. This can lead to incorrect enforcement of virtualization configuration and may cause unexpected traps or denial of service when executing cache-block management instructions in virtualized contexts (V=1).

Frequently asked questions

What is CVE-2026-29649?: NEMU contains an implementation flaw in its RISC-V Hypervisor CSR handling where henvcfg[7:4] (CBIE/CBCFE/CBZE-related fields) is incorrectly masked/updated based on menvcfg[7:4], so a machine-mode write to menvcfg can implicitly modify the hypervisor's environment configuration. This can lead to incorrect enforcement of virtualization configuration and may cause unexpected traps or denial of service when executing cache-block management instructions in virtualized contexts (V=1).
How severe is CVE-2026-29649?: CVE-2026-29649 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-29649 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-29649?: CVE-2026-29649 affects Xiangshan Nemu. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-29649?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-29649 have an EU (EUVD) identifier?: Yes. CVE-2026-29649 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23944.
When was CVE-2026-29649 published?: CVE-2026-29649 was published on 2026-04-20 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:xiangshan:nemu:-:*:*:*:*:*:*:*

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