CVE-2026-23836: HotCRP is conference review software

This month

CRITICAL 9.9UPGRADE

CVE-2026-23836 is a critical-severity flaw (CVSS 9.9) affecting hotcrp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

HotCRP is conference review software. A problem introduced in April 2024 in version 3.1 led to inadequately sanitized code generation for HotCRP formulas which allowed users to trigger the execution of arbitrary PHP code. The problem is patched in release version 3.2.

Why this priority

Critical severity

A fixed release or distro patch exists.

Risk facts

CVSS score	9.9 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-20
Published	2026-01-19
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: hotcrp

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

Am I affected?

Timeline

2026-01-19 18:16 UTCPublished CVE record published
2026-06-17 10:22 UTCUpdated Record last modified

hotcrp hotcrp UPGRADE

Affected: >= 3.0 and < 3.2

Fixed in: 3.2

Safe to downgrade to: a release before 3.0

1. Check installed version

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

2. UPGRADE to 3.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade hotcrp

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 3.0 (Debian / Ubuntu)

apt-cache madison hotcrp sudo apt install hotcrp=<VERSION_BEFORE_3.0> sudo apt-mark hold hotcrp

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

dnf --showduplicates list hotcrp sudo dnf downgrade hotcrp-<VERSION_BEFORE_3.0> sudo dnf versionlock add hotcrp

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-2026-23836?

hotcrp: upgrade to 3.2. Exact commands for each OS are on this page.

Is CVE-2026-23836 being exploited?

CVE-2026-23836 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-2026-23836 affect?

CVE-2026-23836 affects hotcrp. Severity is critical (CVSS 9.9). HotCRP is conference review software. A problem introduced in April 2024 in version 3.1 led to inadequately sanitized code generation for HotCRP formulas which allowed users to trigger the execution of arbitrary PHP code. The problem is pat

How urgent is CVE-2026-23836?

Priority 45/100. Critical severity

Software pages

PHP vulnerabilities

Related CVEs

CVE-2026-23878 MEDIUM 6.5 DOWNGRADE HotCRP is conference review software

References

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