CVE-2024-35875x86/coco: Require seeding RNG with RDRAND on CoCo systems
- 8.4HighCVSS base score
- 0.25%Exploitation in 30 daysEPSS · top 83% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: x86/coco: Require seeding RNG with RDRAND on CoCo systems There are few uses of CoCo that don't rely on working cryptography and hence a working RNG. Unfortunately, the CoCo threat model means that the VM host cannot be trusted and may actively work against guests to extract secrets or manipulate computation. Since a malicious host can modify or observe nearly all inputs to guests, the only remaining source of entropy for CoCo guests is RDRAND. If RDRAND is broken -- due to CPU hardware fault -- the RNG as a whole is meant to gracefully continue on gathering entropy from other sources, but since there aren't other sources on CoCo, this is catastrophic. This is mostly a concern at boot time when initially seeding the RNG, as after that the consequences of a broken RDRAND are much more theoretical. So, try at boot to seed the RNG using 256 bits of RDRAND output. If this fails, panic(). This will also trigger if the system is booted without RDRAND, as RDRAND is essential for a safe CoCo boot. Add this deliberately to be "just a CoCo x86 driver feature" and not part of the RNG itself. Many device drivers and platforms have some desire to contribute something to the RNG, and add_device_randomness() is specifically meant for this purpose. Any driver can call it with seed data of any quality, or even garbage quality, and it can only possibly make the quality of the RNG better or have no effect, but can never make it worse. Rather than trying to build something into the core of the RNG, consider the particular CoCo issue just a CoCo issue, and therefore separate it all out into driver (well, arch/platform) code. [ bp: Massage commit message. ]
Timeline
ID reserved
By Linux
- 2 days later
· 2 days later
Published
- 2 years later
· 2 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High8.4 | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.25% · top 83% of all CVEs (15 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.4.
Affected products
- affected d8aa7eea78a1401cce39b3bb61ead0150044a3df – < 22943e4fe4b3a2dcbadc3d38d5bf840bbdbfe374
- affected d8aa7eea78a1401cce39b3bb61ead0150044a3df – < 453b5f2dec276c1bb4ea078bf8c0da57ee4627e5
- affected d8aa7eea78a1401cce39b3bb61ead0150044a3df – < 08044b08b37528b82f70a87576c692b4e4b7716e
- affected d8aa7eea78a1401cce39b3bb61ead0150044a3df – < 99485c4c026f024e7cb82da84c7951dbe3deb584
- affected 4.15
- unaffected < 4.15
- unaffected 6.1.85 – ≤ 6.1.*
- unaffected 6.6.26 – ≤ 6.6.*
- unaffected 6.8.5 – ≤ 6.8.*
- unaffected 6.9 – ≤ *
References
References4
- https://git.kernel.org/stable/c/22943e4fe4b3a2dcbadc3d38d5bf840bbdbfe374 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/453b5f2dec276c1bb4ea078bf8c0da57ee4627e5 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/08044b08b37528b82f70a87576c692b4e4b7716e (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/99485c4c026f024e7cb82da84c7951dbe3deb584 (opens in a new tab)x_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2024-35593 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2024-35875)Record last updated .