CVE-2026-43507: An issue was discovered in Prosody before 0.12.6 and 1.0.0 through 13.0.0 before 13.0.5

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-43507 is a medium-severity flaw (CVSS 5.3) affecting prosody. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in Prosody before 0.12.6 and 1.0.0 through 13.0.0 before 13.0.5. A Denial of Service can occur via memory exhaustion caused by XML parsing resource amplification from unauthenticated connections.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 72%)
CISA exploited list	No
Weakness	CWE-770
Published	2026-05-01
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: prosody

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

Am I affected?

Timeline

2026-05-01 15:16 UTCPublished CVE record published
2026-06-17 10:49 UTCUpdated Record last modified

prosody prosody UPGRADE

Affected: < 0.12.6 · >= 13.0.0 and < 13.0.5

Fixed in: 0.12.6, 13.0.5

Safe to downgrade to: a release before 13.0.0

1. Check installed version

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

2. UPGRADE to 0.12.6 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade prosody

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 13.0.0 (Debian / Ubuntu)

apt-cache madison prosody sudo apt install prosody=<VERSION_BEFORE_13.0.0> sudo apt-mark hold prosody

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

dnf --showduplicates list prosody sudo dnf downgrade prosody-<VERSION_BEFORE_13.0.0> sudo dnf versionlock add prosody

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-2026-43507?

prosody: upgrade to 0.12.6, 13.0.5. Exact commands for each OS are on this page.

Is CVE-2026-43507 being exploited?

CVE-2026-43507 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-2026-43507 affect?

CVE-2026-43507 affects prosody. Severity is medium (CVSS 5.3). An issue was discovered in Prosody before 0.12.6 and 1.0.0 through 13.0.0 before 13.0.5. A Denial of Service can occur via memory exhaustion caused by XML parsing resource amplification from unauthenticated connections.

How urgent is CVE-2026-43507?

Priority 31/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-43506 MEDIUM 5.3 UPGRADE An issue was discovered in Prosody before 0.12.6 and 1.0.0 through 13.0.0 before 13.0.5
CVE-2026-43505 MEDIUM 6.5 UPGRADE An issue was discovered in Prosody before 0.12.6 and 1.0.0 through 13.0.0 before 13.0.5, when mod_proxy65 is e
CVE-2026-43504 MEDIUM 6.5 UPGRADE An issue was discovered in Prosody before 0.12.6 and 1.0.0 through 13.0.0 before 13.0.5, when mod_proxy65 is e

References

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