CVE catalog

CVE-2026-25834

Mbed TLS v3.3.0 up to 3.6.5 and 4.0.0 allows Algorithm Downgrade.

Severity: Medium · CVSS 6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Published: Apr 1, 2026, 6:16:28 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.14% · Oct 25, 2026

Mbed TLS v3.3.0 up to 3.6.5 and 4.0.0 allows Algorithm Downgrade.

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	mbedtls	sid	`3.6.7-3`	fixed
Debian	mbedtls	forky	`3.6.7-3`	fixed
Debian	mbedtls	trixie	`3.6.6-0.1~deb13u1`	fixed
Debian	mbedtls	bookworm	`2.28.3-1`	not affected
Cpe	mbed_tls	Not reported	`3.6.6`	fixed
Cpe	mbed_tls	Not reported	Not reported	unknown
Cpe	mbedtls	Not reported	Not reported	not affected
Alpine	mbedtls	3.20	`3.6.6-r0`	fixed
Alpine	mbedtls	3.21	`3.6.6-r0`	fixed
Alpine	mbedtls	3.22	`3.6.6-r0`	fixed
Alpine	mbedtls	3.23	`3.6.6-r0`	fixed
Alpine	mbedtls	3.24	`3.6.6-r0`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	mbedtls	source	sid	`3.6.6-0.1`	not yet assigned	Not reported	[1133841]
Debian	mbedtls	source	forky	`3.6.6-0.1`	not yet assigned	Not reported	[1133841]
Debian	mbedtls	source	trixie	`3.6.6-0.1~deb13u1`	not yet assigned	Not reported	[1133841]
Debian	mbedtls	source	bookworm	`Not affected`	unimportant	Not reported	[1133841]
Cpe	mbed_tls	cpe	Not reported	`3.6.6`	Not reported	Not reported	Not reported
Alpine	mbedtls	apk	3.20	`3.6.6-r0`	Not reported	ALPINE-CVE-2026-25834	Not reported
Alpine	mbedtls	apk	3.21	`3.6.6-r0`	Not reported	ALPINE-CVE-2026-25834	Not reported
Alpine	mbedtls	apk	3.22	`3.6.6-r0`	Not reported	ALPINE-CVE-2026-25834	Not reported
Alpine	mbedtls	apk	3.23	`3.6.6-r0`	Not reported	ALPINE-CVE-2026-25834	Not reported
Alpine	mbedtls	apk	3.24	`3.6.6-r0`	Not reported	ALPINE-CVE-2026-25834	Not reported

[Debian bug #1133841]

OpenFactory catalog packages

[Debian 13 (Trixie)]

[libmbedcrypto16]Affected
Source package: [mbedtls]
Details (2)
- 3.6.5-0.1~deb13u1 · amd64 · trixie
  Affected · Fixed: 3.6.6-0.1~deb13u1
  nvd · mbedtls · debian · 13
- 3.6.5-0.1~deb13u1 · arm64 · trixie
  Affected · Fixed: 3.6.6-0.1~deb13u1
  nvd · mbedtls · debian · 13
[libmbedtls21]Affected
Source package: [mbedtls]
Details (2)
- 3.6.5-0.1~deb13u1 · amd64 · trixie
  Affected · Fixed: 3.6.6-0.1~deb13u1
  nvd · mbedtls · debian · 13
- 3.6.5-0.1~deb13u1 · arm64 · trixie
  Affected · Fixed: 3.6.6-0.1~deb13u1
  nvd · mbedtls · debian · 13
[libmbedtls-dev]Affected
Source package: [mbedtls]
Details (2)
- 3.6.5-0.1~deb13u1 · amd64 · trixie
  Affected · Fixed: 3.6.6-0.1~deb13u1
  nvd · mbedtls · debian · 13
- 3.6.5-0.1~deb13u1 · arm64 · trixie
  Affected · Fixed: 3.6.6-0.1~deb13u1
  nvd · mbedtls · debian · 13
[libmbedtls-doc]Affected
Source package: [mbedtls]
Details (2)
- 3.6.5-0.1~deb13u1 · all · trixie
  Affected · Fixed: 3.6.6-0.1~deb13u1
  nvd · mbedtls · debian · 13
- 3.6.5-0.1~deb13u1 · all · trixie
  Affected · Fixed: 3.6.6-0.1~deb13u1
  nvd · mbedtls · debian · 13
[libmbedx509-7]Affected
Source package: [mbedtls]
Details (2)
- 3.6.5-0.1~deb13u1 · amd64 · trixie
  Affected · Fixed: 3.6.6-0.1~deb13u1
  nvd · mbedtls · debian · 13
- 3.6.5-0.1~deb13u1 · arm64 · trixie
  Affected · Fixed: 3.6.6-0.1~deb13u1
  nvd · mbedtls · debian · 13

[Debian 12 (Bookworm)]

[libmbedcrypto7]Not affected
Source package: [mbedtls]
Details (2)
- 2.28.3-1 · amd64 · bookworm
  Not affected
  nvd · mbedtls · debian · bookworm
- 2.28.3-1 · arm64 · bookworm
  Not affected
  nvd · mbedtls · debian · bookworm
[libmbedtls14]Not affected
Source package: [mbedtls]
Details (2)
- 2.28.3-1 · amd64 · bookworm
  Not affected
  nvd · mbedtls · debian · bookworm
- 2.28.3-1 · arm64 · bookworm
  Not affected
  nvd · mbedtls · debian · bookworm
[libmbedtls-dev]Not affected
Source package: [mbedtls]
Details (2)
- 2.28.3-1 · amd64 · bookworm
  Not affected
  nvd · mbedtls · debian · bookworm
- 2.28.3-1 · arm64 · bookworm
  Not affected
  nvd · mbedtls · debian · bookworm
[libmbedtls-doc]Not affected
Source package: [mbedtls]
Details (2)
- 2.28.3-1 · all · bookworm
  Not affected
  nvd · mbedtls · debian · bookworm
- 2.28.3-1 · all · bookworm
  Not affected
  nvd · mbedtls · debian · bookworm
[libmbedx509-1]Not affected
Source package: [mbedtls]
Details (2)
- 2.28.3-1 · amd64 · bookworm
  Not affected
  nvd · mbedtls · debian · bookworm
- 2.28.3-1 · arm64 · bookworm
  Not affected
  nvd · mbedtls · debian · bookworm

Observed: Oct 23, 2026, 10:35:53 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [SUSE security advisories and VEX]