CVE catalog

CVE-2026-9545

Severity: High · CVSS 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Published: Jun 23, 2026, 10:00:00 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.41% · Oct 25, 2026

In this scenario, libcurl first uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate. When libcurl returns to the hostname the second time with a cached SSL session (`CURLOPT_SSL_SESSIONID_CACHE` is not disabled) and early data enabled (the `CURLSSLOPT_EARLYDATA` bit is set in `CURLOPT_SSL_OPTIONS`), libcurl might send off the second request's bytes on that new connection *before* enforcing the certificate verification failure. Potentially leaking sensitive information.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	curl	sid	`8.23.0-1`	fixed
Debian	curl	forky	`8.22.0-1`	fixed
Debian	curl	trixie	`8.14.1-2+deb13u5`	vulnerable
Debian	curl	trixie-security	`8.14.1-2+deb13u7`	vulnerable
Debian	curl	bookworm	`7.88.1-10+deb12u15`	not affected
Debian	curl	bookworm-security	`7.88.1-10+deb12u5`	not affected
Cpe	curl	Not reported	`8.5.0-2ubuntu10.10`	fixed
Cpe	libcurl3t64-gnutls	Not reported	`8.5.0-2ubuntu10.10`	fixed
Cpe	libcurl4-doc	Not reported	`8.5.0-2ubuntu10.10`	fixed
Cpe	libcurl4-gnutls-dev	Not reported	`8.5.0-2ubuntu10.10`	fixed
Cpe	libcurl4-openssl-dev	Not reported	`8.5.0-2ubuntu10.10`	fixed
Cpe	libcurl4t64	Not reported	`8.5.0-2ubuntu10.10`	fixed
Cpe	curl	Not reported	`8.21.0`	fixed
Cpe	curl	Not reported	Not reported	not affected
Cpe	curl	Not reported	`8.21.0`	fixed
Alpine	curl	3.23	`8.22.0-r0`	fixed
Alpine	curl	3.24	`8.21.0-r0`	fixed
Ubuntu	curl	25.10	`8.12.1-3ubuntu1`	vulnerable
Ubuntu	curl	25.10	`8.13.0-5ubuntu1`	vulnerable
Ubuntu	curl	25.10	`8.14.1-1ubuntu2`	vulnerable
Ubuntu	curl	25.10	`8.14.1-1ubuntu3`	vulnerable
Ubuntu	curl	25.10	`8.14.1-2ubuntu1`	vulnerable
Ubuntu	curl	25.10	`8.14.1-2ubuntu1.1`	vulnerable
Ubuntu	curl	25.10	`8.14.1-2ubuntu1.2`	vulnerable
Ubuntu	curl	25.10	`8.14.1-2ubuntu1.3`	vulnerable
Ubuntu	curl	25.10	`8.14.1-2ubuntu1.4`	fixed
Ubuntu	curl	26.04	`8.14.1-2ubuntu1`	vulnerable
Ubuntu	curl	26.04	`8.17.0-1ubuntu1`	vulnerable
Ubuntu	curl	26.04	`8.18.0-1ubuntu1`	vulnerable
Ubuntu	curl	26.04	`8.18.0-1ubuntu2`	vulnerable
Ubuntu	curl	26.04	`8.18.0-1ubuntu2.1`	vulnerable
Ubuntu	curl	26.04	`8.18.0-1ubuntu2.2`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	curl	source	sid	`8.21.0~rc2-1`	not yet assigned	Not reported	Not reported
Debian	curl	source	forky	`8.21.0~rc2-1`	not yet assigned	Not reported	Not reported
Debian	curl	source	trixie	`(unfixed)`	not yet assigned	Not reported	Not reported
Debian	curl	source	bookworm	`Not affected`	unimportant	Not reported	Not reported
Cpe	curl	cpe	Not reported	`8.5.0-2ubuntu10.10`	Not reported	Not reported	Not reported
Cpe	libcurl3t64-gnutls	cpe	Not reported	`8.5.0-2ubuntu10.10`	Not reported	Not reported	Not reported
Cpe	libcurl4-doc	cpe	Not reported	`8.5.0-2ubuntu10.10`	Not reported	Not reported	Not reported
Cpe	libcurl4-gnutls-dev	cpe	Not reported	`8.5.0-2ubuntu10.10`	Not reported	Not reported	Not reported
Cpe	libcurl4-openssl-dev	cpe	Not reported	`8.5.0-2ubuntu10.10`	Not reported	Not reported	Not reported
Cpe	libcurl4t64	cpe	Not reported	`8.5.0-2ubuntu10.10`	Not reported	Not reported	Not reported
Cpe	curl	cpe	Not reported	`8.21.0`	Not reported	Not reported	Not reported
Cpe	curl	cpe	Not reported	`8.21.0`	Not reported	NVD-CVE-2026-9545	Not reported
Alpine	curl	apk	3.23	`8.22.0-r0`	Not reported	ALPINE-CVE-2026-9545	Not reported
Alpine	curl	apk	3.24	`8.21.0-r0`	Not reported	ALPINE-CVE-2026-9545	Not reported
Ubuntu	curl	deb	25.10	`8.14.1-2ubuntu1.4`	Not reported	UBUNTU-CVE-2026-9545	Not reported
Ubuntu	curl	deb	26.04	`8.18.0-1ubuntu2.2`	Not reported	UBUNTU-CVE-2026-9545	Not reported

Notes

[trixie] curl: Minor issue

OpenFactory catalog packages

[Debian 13 (Trixie)]

[curl]Affected
Details (5)
- 8.14.1-2+deb13u4 · amd64 · trixie
  Affected
  nvd · curl · debian · 13
- 8.14.1-2+deb13u4 · arm64 · trixie
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · amd64 · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · arm64 · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.14.1-2+deb13u7 · amd64 · trixie-security
  Affected
  nvd · curl · debian · 13
[libcurl3t64-gnutls]Affected
Source package: [curl]
Details (5)
- 8.14.1-2+deb13u4 · amd64 · trixie
  Affected
  nvd · curl · debian · 13
- 8.14.1-2+deb13u4 · arm64 · trixie
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · amd64 · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · arm64 · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.14.1-2+deb13u7 · amd64 · trixie-security
  Affected
  nvd · curl · debian · 13
[libcurl4-doc]Affected
Source package: [curl]
Details (5)
- 8.14.1-2+deb13u4 · all · trixie
  Affected
  nvd · curl · debian · 13
- 8.14.1-2+deb13u4 · all · trixie
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · all · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · all · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.14.1-2+deb13u7 · all · trixie-security
  Affected
  nvd · curl · debian · 13
[libcurl4-gnutls]Affected
Source package: [curl]
Details (2)
- 8.21.0-2~bpo13+1 · amd64 · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · arm64 · trixie-backports
  Affected
  nvd · curl · debian · 13
[libcurl4-gnutls-dev]Affected
Source package: [curl]
Details (5)
- 8.14.1-2+deb13u4 · amd64 · trixie
  Affected
  nvd · curl · debian · 13
- 8.14.1-2+deb13u4 · arm64 · trixie
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · amd64 · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · arm64 · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.14.1-2+deb13u7 · amd64 · trixie-security
  Affected
  nvd · curl · debian · 13
[libcurl4-openssl-dev]Affected
Source package: [curl]
Details (5)
- 8.14.1-2+deb13u4 · amd64 · trixie
  Affected
  nvd · curl · debian · 13
- 8.14.1-2+deb13u4 · arm64 · trixie
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · amd64 · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · arm64 · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.14.1-2+deb13u7 · amd64 · trixie-security
  Affected
  nvd · curl · debian · 13
[libcurl4t64]Affected
Source package: [curl]
Details (5)
- 8.14.1-2+deb13u4 · amd64 · trixie
  Affected
  nvd · curl · debian · 13
- 8.14.1-2+deb13u4 · arm64 · trixie
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · amd64 · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.21.0-2~bpo13+1 · arm64 · trixie-backports
  Affected
  nvd · curl · debian · 13
- 8.14.1-2+deb13u7 · amd64 · trixie-security
  Affected
  nvd · curl · debian · 13

[Debian 12 (Bookworm)]

[curl]Not affected
Details (6)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 8.14.1-2+deb13u2~bpo13+1 · amd64 · bookworm-backports
  Not affected
  nvd · curl · debian · bookworm
- 8.14.1-2+deb13u2~bpo13+1 · arm64 · bookworm-backports
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
[libcurl3-gnutls]Not affected
Source package: [curl]
Details (6)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 8.14.1-2+deb13u2~bpo13+1 · amd64 · bookworm-backports
  Not affected
  nvd · curl · debian · bookworm
- 8.14.1-2+deb13u2~bpo13+1 · arm64 · bookworm-backports
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
[libcurl3-nss]Not affected
Source package: [curl]
Details (4)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
[libcurl4]Not affected
Source package: [curl]
Details (6)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 8.14.1-2+deb13u2~bpo13+1 · amd64 · bookworm-backports
  Not affected
  nvd · curl · debian · bookworm
- 8.14.1-2+deb13u2~bpo13+1 · arm64 · bookworm-backports
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
[libcurl4-doc]Not affected
Source package: [curl]
Details (6)
- 7.88.1-10+deb12u15 · all · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u15 · all · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 8.14.1-2+deb13u2~bpo13+1 · all · bookworm-backports
  Not affected
  nvd · curl · debian · bookworm
- 8.14.1-2+deb13u2~bpo13+1 · all · bookworm-backports
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · all · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · all · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
[libcurl4-gnutls-dev]Not affected
Source package: [curl]
Details (6)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 8.14.1-2+deb13u2~bpo13+1 · amd64 · bookworm-backports
  Not affected
  nvd · curl · debian · bookworm
- 8.14.1-2+deb13u2~bpo13+1 · arm64 · bookworm-backports
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
[libcurl4-nss-dev]Not affected
Source package: [curl]
Details (4)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
[libcurl4-openssl-dev]Not affected
Source package: [curl]
Details (6)
- 7.88.1-10+deb12u15 · amd64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u15 · arm64 · bookworm
  Not affected
  nvd · curl · debian · bookworm
- 8.14.1-2+deb13u2~bpo13+1 · amd64 · bookworm-backports
  Not affected
  nvd · curl · debian · bookworm
- 8.14.1-2+deb13u2~bpo13+1 · arm64 · bookworm-backports
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · amd64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm
- 7.88.1-10+deb12u5 · arm64 · bookworm-security
  Not affected
  nvd · curl · debian · bookworm

Observed: Oct 27, 2026, 7:14:03 AM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]