Vulnerability · RUSTSEC-2026-0385
Non-constant-time mask generation and comparisons
Published Oct 23, 2026 · RustSec Rust
Last checked Oct 24, 2026. A connected source was read within the last 7 days.
Open the advisory
Exploitation likelihood is not on this record for RUSTSEC-2026-0385. A missing EPSS score is not a low risk. Compare RustSec Rust with the linked advisory before you change production.
Gaps on this record
- No version range is stored. A customer cannot check an installed version against this record.
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- EPSS is missing. A missing score is not a low risk.
Same product and reporting
- RUSTSEC-2026-0387 · Unknown
- RUSTSEC-2026-0384 · Unknown
- RUSTSEC-2026-0376 · Low
- RUSTSEC-2026-0377 · Low
- RUSTSEC-2026-0379 · Critical
- Severity
- Unknown—
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- Awaiting synchronization with FIRST
- Remediation
- Not established
- Affected products
- RustSec Rust
## Summary The type has mask generation functions for each unsigned integer size ( , , , , ). These are and therefore can't reuse the -backed mask generation in the crate that's otherwise used to ensure constant-time. In releases prior to v0.4.4, the generated code from these functions could include a branch on commonly used platforms. This has been corrected in this release and now verified on several platforms using BINSEC. Additionally, comparison operations provided via and intended to work in constant-time were generating branches on 32-bit targets. This has been resolved via a special ca
No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.
How to fix RUSTSEC-2026-0385
No stored fix
No vendor fix text is stored. Use the linked advisory before you change production.
Version check
No version range is stored, so an installed version cannot be checked on this page.
Advisory
Open the rustsec record and follow its fix.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
Exploitation likelihood is not on this record for RUSTSEC-2026-0385. A missing EPSS score is not a low risk. Compare RustSec Rust with the linked advisory before you change production.
Which versions are affected?
Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
No weakness class is stored. EPSS is not on this record yet. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Oct 23, 2026 · RustSec Advisory DB
Detected
## Summary The type has mask generation functions for each unsigned integer size ( , , , , ). These are and therefore can't reuse the -backed mask generation in the crate that's otherwise used to ensure constant-time. In releases prior to v0.4.4, the generated code from these functions could include a branch on commonly used platforms. This has been corrected in this release and now verified on se
Sources
- RustSec Advisory DBVendor advisoryRUSTSEC-2026-0385
## Summary The type has mask generation functions for each unsigned integer size ( , , , , ). These are and therefore can't reuse the -backed mask generation in the crate that's otherwise used to ensure constant-time. In releases prior to v0.4.4, the generated code from these fun
crates.io
Freshness
Last verified in this catalog Unknown date. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.
- RustSec Advisory DBOct 24, 2026