CVE-2026-63074: Issue summary: The OpenSSL Certificate Management Protocol (CMP) caches additional certificates (extraCerts) s

Q: How do I fix CVE-2026-63074?

openssl: upgrade to 3.0.22, 3.4.7, 3.5.8, 3.6.4, 4.0.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-63074 being exploited?

CVE-2026-63074 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-63074 affect?

CVE-2026-63074 affects openssl. Severity is medium (CVSS 5.9). Issue summary: The OpenSSL Certificate Management Protocol (CMP) caches additional certificates (extraCerts) sent in a CMP message, but never expunges them (for instance if they are invalid). If a server reuses an OSSL_CMP_CTX frequently,

Q: How urgent is CVE-2026-63074?

Priority 43/100. Remotely exploitable, no login, no user action; On your watchlist

This month

MEDIUM 5.9REMOTEWATCHLISTUPGRADE

CVE-2026-63074 is a medium-severity flaw (CVSS 5.9) affecting openssl. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Issue summary: The OpenSSL Certificate Management Protocol (CMP) caches additional certificates (extraCerts) sent in a CMP message, but never expunges them (for instance if they are invalid). If a server reuses an OSSL_CMP_CTX frequently, this cache of extraCerts may grow unboundedly, and a malicious client may flood a CMP server with requests driving this growth. Impact summary: Users utilizing a CMP server that reuses a single OSSL_CMP_CTX fo

Why this priority

Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Weakness	CWE-770
Published	2026-08-25
Last modified	2026-09-11

Publisher (CNA): OpenSSL Software Foundation · Vendor: openssl

Last updated 2026-09-11 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-25 13:19 UTCPublished CVE record published
2026-09-11 21:16 UTCUpdated Record last modified

openssl openssl UPGRADE

Affected: >= 3.0.0 and < 3.0.22 · >= 3.4.0 and < 3.4.7 · >= 3.5.0 and < 3.5.8 · >= 3.6.0 and < 3.6.4 · >= 4.0.0 and < 4.0.2

Fixed in: 3.0.22, 3.4.7, 3.5.8, 3.6.4, 4.0.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy openssl || rpm -q openssl || openssl --version

2. UPGRADE to 3.0.22 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade openssl

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade openssl

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-63074?

openssl: upgrade to 3.0.22, 3.4.7, 3.5.8, 3.6.4, 4.0.2. Exact commands for each OS are on this page.

Is CVE-2026-63074 being exploited?

CVE-2026-63074 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-63074 affect?

CVE-2026-63074 affects openssl. Severity is medium (CVSS 5.9). Issue summary: The OpenSSL Certificate Management Protocol (CMP) caches additional certificates (extraCerts) sent in a CMP message, but never expunges them (for instance if they are invalid). If a server reuses an OSSL_CMP_CTX frequently,

How urgent is CVE-2026-63074?

Priority 43/100. Remotely exploitable, no login, no user action; On your watchlist

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References

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