safeurl validated address is not bound to the request, allowing DNS rebinding (CVE-2026-77972) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-77972

safeurl validated address is not bound to the request, allowing DNS rebinding

Answer in brief

CVE-2026-77972 records a Unknown severity vulnerability in safeurl validated address is not bound to the request, allowing DNS rebinding. The current sources do not mark it as known exploited. The current feed maps Slab/safeurl (generic), Slab/safeurl (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 15, 2026Updated Sep 15, 2026Source checked Sep 15, 2026First seen by HOL Sep 15, 2026Material review Sep 15, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Slab/safeurl (generic), Slab/safeurl (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Slab/safeurlgeneric	>=0.1.0 <*	*
Slab/safeurlgeneric	>=feabbd0a13f83028ab24b71710526e9da9841f70 <*	*

Recommended response

Check inventory. Check lockfiles and deployed manifests for Slab/safeurl, Slab/safeurl.
Review the reported fix. Update Slab/safeurl to *; Slab/safeurl to * if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 15, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 15, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 15, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.