CVE-2026-32877: Botan is a C++ cryptography library

Routine

HIGH 8.2REMOTEUPGRADE

CVE-2026-32877 is a high-severity flaw (CVSS 8.2) affecting botan. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Botan is a C++ cryptography library. From version 2.3.0 to before version 3.11.0, during SM2 decryption, the code that checked the authentication code value (C3) failed to check that the encoded value was of the expected length prior to comparison. An invalid ciphertext can cause a heap over-read of up to 31 bytes, resulting in a crash or potentially other undefined behavior. This issue has been patched in version 3.11.0.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	8.2 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 79%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-03-30
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: botan project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-30 21:17 UTCPublished CVE record published
2026-06-17 10:36 UTCUpdated Record last modified

botan project botan UPGRADE

Affected: >= 2.3.0 and < 3.11.0

Fixed in: 3.11.0

Safe to downgrade to: a release before 2.3.0

1. Check installed version

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

2. UPGRADE to 3.11.0 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade botan

Note

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

3. If no update is available yet, DOWNGRADE to a release before 2.3.0 (Debian / Ubuntu)

apt-cache madison botan sudo apt install botan=<VERSION_BEFORE_2.3.0> sudo apt-mark hold botan

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list botan sudo dnf downgrade botan-<VERSION_BEFORE_2.3.0> sudo dnf versionlock add botan

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2026-32877?

botan: upgrade to 3.11.0. Exact commands for each OS are on this page.

Is CVE-2026-32877 being exploited?

CVE-2026-32877 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-2026-32877 affect?

CVE-2026-32877 affects botan. Severity is high (CVSS 8.2). Botan is a C++ cryptography library. From version 2.3.0 to before version 3.11.0, during SM2 decryption, the code that checked the authentication code value (C3) failed to check that the encoded value was of the expected length prior to com

How urgent is CVE-2026-32877?

Priority 39/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-44378 HIGH 7.5 UPGRADE Botan is a C++ cryptography library
CVE-2026-34580 HIGH 7.5 DOWNGRADE Botan is a C++ cryptography library
CVE-2026-34582 CRITICAL 9.1 UPGRADE Botan is a C++ cryptography library
CVE-2026-32884 MEDIUM 5.9 UPGRADE Botan is a C++ cryptography library
CVE-2026-32883 MEDIUM 5.9 UPGRADE Botan is a C++ cryptography library

References

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