CVE-2026-25834

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

Published: 2026-04-01 Last update: 2026-06-05 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-25834 is rated Low Risk (28.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.03%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-25834

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-02 — 0.03% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-25834

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 2.5 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-25834

OS Trackers for CVE-2026-25834

vendor priority summary link
alpine — CVE-2026-25834: 1 source package rows (mbedtls); 5 state rows across 5 repos (3.20-main, 3.21-main, 3.22-main, 3.23-main, edge-main); fixed 5, open 0. https://security.alpinelinux.org/vuln/CVE-2026-25834
debian unimportant CVE-2026-25834 unimportant priority: Debian including 1 source packages (mbedtls), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2026-25834
redhat medium — https://access.redhat.com/security/cve/CVE-2026-25834
suse medium CVE-2026-25834 severity moderate: SUSE including 79 source package names (libeverest-3.6.6-1.1, libeverest-x86-64-v3-3.6.6-1.1, …), 814 product×package rows across 28 product lines (SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS, … (28 product lines)): Known Not Affected 803, Fixed 11. https://www.suse.com/security/cve/CVE-2026-25834/
ubuntu medium CVE-2026-25834 medium priority: Ubuntu including 1 source packages (mbedtls), 7 status rows across 7 suites (bionic, focal, jammy, noble, questing, upstream, xenial): needs-triage 7. https://ubuntu.com/security/CVE-2026-25834

Affected software / configurations for CVE-2026-25834

Vendor Product Version Raw CPE
trustedfirmware mbed_tls >= 3.3.0, < 3.6.6 cpe:2.3:a:trustedfirmware:mbed_tls:*:*:*:*:*:*:*:*
trustedfirmware mbed_tls 4.0.0 cpe:2.3:a:trustedfirmware:mbed_tls:4.0.0:*:*:*:*:*:*:*

References for CVE-2026-25834

cvelogic Threat Intelligence