Critical severity9.8NVD Advisory· Published Jul 3, 2026· Updated Sep 15, 2026
CVE-2026-11856
CVE-2026-11856
Description
Successfully using libcurl to do a transfer to a specific HTTP origin (hostA) with Digest authentication and then changing the origin to a different one (hostB) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the Authorization: header field meant for hostA, to hostB.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
18- osv-coords15 versionspkg:apk/chainguard/eco-python-curl-minimal-binpkg:apk/chainguard/eco-python-curl-minimal-docpkg:apk/chainguard/eco-python-curl-nghttp2-staticpkg:apk/chainguard/eco-python-curl-minimal-staticpkg:rpm/opensuse/curl&distro=openSUSE%20Tumbleweedpkg:rpm/almalinux/curlpkg:rpm/almalinux/libcurlpkg:rpm/almalinux/libcurl-develpkg:rpm/almalinux/libcurl-minimalpkg:apk/chainguard/eco-python-curlpkg:apk/chainguard/eco-python-curl-minimalpkg:apk/chainguard/eco-python-curl-minimal-devpkg:apk/chainguard/eco-python-curl-nghttp2-binpkg:apk/chainguard/eco-python-curl-nghttp2pkg:apk/chainguard/eco-python-curl-nghttp2-dev
< 8.21.0-r0+ 14 more
- (no CPE)range: < 8.21.0-r0
- (no CPE)range: < 8.21.0-r0
- (no CPE)range: < 8.21.0-r0
- (no CPE)range: < 8.21.0-r0
- (no CPE)range: < 8.21.0-1.1
- (no CPE)range: < 8.12.1-4.el10_2.6
- (no CPE)range: < 8.12.1-4.el10_2.6
- (no CPE)range: < 8.12.1-4.el10_2.6
- (no CPE)range: < 8.12.1-4.el10_2.6
- (no CPE)range: < 8.21.0-r0
- (no CPE)range: < 8.21.0-r0
- (no CPE)range: < 8.21.0-r0
- (no CPE)range: < 8.21.0-r0
- (no CPE)range: < 8.21.0-r0
- (no CPE)range: < 8.21.0-r0
Patches
Vulnerability mechanics
References
3- curl.se/docs/CVE-2026-11856.htmlnvdPatchVendor Advisory
- hackerone.com/reports/3793260nvdExploitIssue TrackingThird Party Advisory
- curl.se/docs/CVE-2026-11856.jsonnvdVendor Advisory
News mentions
1- 25-Year-Old Vulnerability in cURL Used by 30 Billion Devices Finally PatchedCyber Security News · Jun 25, 2026