CVE-2023-33613: axTLS v2.1.5 was discovered to contain a heap buffer overflow in the bi_import function in axtls-code/crypto/b

Routine

MEDIUM 5.5DOWNGRADE

CVE-2023-33613 is a medium-severity flaw (CVSS 5.5) affecting axtls. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

axTLS v2.1.5 was discovered to contain a heap buffer overflow in the bi_import function in axtls-code/crypto/bigint.c. This vulnerability allows attackers to cause a Denial of Service (DoS) when parsing a private key.

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 77%)
CISA exploited list	No
Weakness	CWE-787
Published	2023-06-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: axtls project

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

Am I affected?

Timeline

2023-06-06 18:15 UTCPublished CVE record published
2026-06-17 06:01 UTCUpdated Record last modified

axtls project axtls DOWNGRADE

Affected: 2.1.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.1.5

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.1.5 (Debian / Ubuntu)

apt-cache madison axtls sudo apt install axtls=<VERSION_BEFORE_2.1.5> sudo apt-mark hold axtls

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list axtls sudo dnf downgrade axtls-<VERSION_BEFORE_2.1.5> sudo dnf versionlock add axtls

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-2023-33613?

axtls: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-33613 being exploited?

CVE-2023-33613 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-2023-33613 affect?

CVE-2023-33613 affects axtls. Severity is medium (CVSS 5.5). axTLS v2.1.5 was discovered to contain a heap buffer overflow in the bi_import function in axtls-code/crypto/bigint.c. This vulnerability allows attackers to cause a Denial of Service (DoS) when parsing a private key.

How urgent is CVE-2023-33613?

Priority 30/100. Public exploit reference

References

← Back to latest CVEs