Description (CNA)
Time-of-check Time-of-use (TOCTOU) Race Condition in Slab safeurl allows an attacker who controls a hostname's DNS responses to reach internal network destinations that validation rejected. Validation returns a verdict and not the address it approved, so the HTTP clients the library ships receive the original hostname and resolve it a second time when the request is made. An attacker who controls the authoritative DNS for a name can answer the first lookup with a permitted address and the second with a blocked one, and the request then reaches a destination validation never approved. The same window opens without an attacker whenever a name legitimately resolves to different addresses across lookups, such as short record lifetimes or rotation between several addresses. This issue affects safeurl: from 0.1.0 onward.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Slab / safeurl | affected 0.1.0 before * |
| Slab / safeurl | affected feabbd0a13f83028ab24b71710526e9da9841f70 before * |
CWE
CWE-367
References
- https://cna.erlef.org/cves/CVE-2026-77972.html
- https://osv.dev/vulnerability/EEF-CVE-2026-77972
- https://github.com/slab/safeurl-elixir/commit/feabbd0a13f83028ab24b71710526e9da9841f70
ADP enrichment
No English description supplied.
No references supplied.