CVE-2025-54771: Grub2: use-after-free in grub_file_close()

mediumCVSS 4.9CVE-2025-54771

CSIRTS triage

vendor: GNU product: GRUB2 Memory corruption

What: A use-after-free vulnerability exists in the grub_file_close() function.
Who is affected: GRUB2 bootloader installations are affected when handling file operations.
Urgency: Medium priority; memory corruption could lead to code execution but requires specific conditions to trigger.
Action: Update GRUB2 to a version with the use-after-free fix applied.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 4.9
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-54771

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2025-547710.15% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 4% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2025-54771	coverage & exploitation status	NVD · CVE.org

Recent advisories for Grub2

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

mediumCVE-2025-54770: Grub2: use-after-free in net_set_vlanmsrc · 2026-08-06
mediumCVE-2024-56738: GNU GRUB (aka GRUB2) through 2.12 does not use a constant-time algorithm for grub_crypto_memcm…msrc · 2026-08-06