CVE-2024-56738: GNU GRUB (aka GRUB2) through 2.12 does not use a constant-time algorithm for grub_crypto_memcmp and thus allows side-channel attacks.
CSIRTS triage
- What
- The grub_crypto_memcmp function uses a non-constant-time algorithm enabling timing side-channel attacks to leak cryptographic secrets.
- Who is affected
- GRUB installations using cryptographic verification with versions through 2.12.
- Urgency
- Medium severity (CVSS 6.7); side-channel attacks require local access and multiple samples but can compromise GRUB security.
- Action
- Update GRUB to a version after 2.12 with constant-time comparison implementation.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-56738
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-2024-567380.41% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 34% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2024-56738 | coverage & exploitation status | NVD · CVE.org |
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