sending old referer

Answer in brief

CVE-2026-9546 records a High severity (CVSS 7.5) vulnerability in sending old referer. The current sources do not mark it as known exploited. The current feed maps curl/curl (generic), curl/curl (generic), curl/curl (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 Jul 3, 2026Updated Sep 15, 2026Source checked Sep 15, 2026First seen by HOL Jul 3, 2026Material review Sep 15, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.5
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 7.5. 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 curl/curl (generic), curl/curl (generic), curl/curl (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
curl/curlgeneric	>=8.18.0 <8.20.1	8.20.1
curl/curlgeneric	>=2cb868242dc2ac9cd52ee64987ef51d5964a56f9 <862e8a74a84478d82973471b4f49dc2746c1780e	862e8a74a84478d82973471b4f49dc2746c1780e
curl/curlgeneric	8.20.0 \|\| 8.19.0 \|\| 8.18.0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for curl/curl, curl/curl, curl/curl.
Review the reported fix. Update curl/curl to 8.20.1; curl/curl to 862e8a74a84478d82973471b4f49dc2746c1780e if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Jul 3, 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
Jul 3, 2026

Sources and claim methodology

Upstream source description

A vulnerability in libcurl caused the HTTP `Referer:` header to persist even when explicitly cleared. While the documentation states that passing NULL to `CURLOPT_REFERER` suppresses the header, the option failed to clear the internal state. As a result, the previous referrer string was erroneously reused and sent in subsequent requests, potentially leaking sensitive information to unintended servers.

Quoted source text, attributed separately from HOL analysis.