secure cookie attribute bypass with tab

Answer in brief

CVE-2026-80255 records a Unknown severity vulnerability in secure cookie attribute bypass with tab. The current sources do not mark it as known exploited. The current feed maps 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 Sep 6, 2026Updated Sep 6, 2026Source checked Sep 6, 2026First seen by HOL Sep 6, 2026Material review Sep 6, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

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 curl/curl (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
curl/curlgeneric	8.21.0 \|\| 8.20.0 \|\| 8.19.0 \|\| 8.18.0 \|\| 8.17.0 \|\| 8.16.0 \|\| 8.15.0 \|\| 8.14.1 \|\| 8.14.0 \|\| 8.13.0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for curl/curl.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 6, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 6, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 6, 2026

Sources and claim methodology

Upstream source description

A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of space (ascii code 32) immediately before the `Secure` attribute causes curl to store the cookie without its Secure flag. The cookie might then wrongfully be sent over plaintext HTTP on subsequent requests to the same host.

Quoted source text, attributed separately from HOL analysis.