CVE-2026-23878: HotCRP is conference review software

Routine

MEDIUM 6.5DOWNGRADE

CVE-2026-23878 is a medium-severity flaw (CVSS 6.5) 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. Starting in commit aa20ef288828b04550950cf67c831af8a525f508 and prior to commit ceacd5f1476458792c44c6a993670f02c984b4a0, authors with at least one submission on a HotCRP site could use the document API to download any documents (PDFs, attachments) associated with any submission. The problem was patched in commit ceacd5f1476458792c44c6a993670f02c984b4a0.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 76%)
CISA exploited list	No
Weakness	CWE-201
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 19:16 UTCPublished CVE record published
2026-06-17 10:22 UTCUpdated Record last modified

hotcrp hotcrp DOWNGRADE

Affected: 3.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.1

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 3.1 (Debian / Ubuntu)

apt-cache madison hotcrp sudo apt install hotcrp=<VERSION_BEFORE_3.1> sudo apt-mark hold hotcrp

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

dnf --showduplicates list hotcrp sudo dnf downgrade hotcrp-<VERSION_BEFORE_3.1> 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-2026-23878?

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

Is CVE-2026-23878 being exploited?

CVE-2026-23878 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-2026-23878 affect?

CVE-2026-23878 affects hotcrp. Severity is medium (CVSS 6.5). HotCRP is conference review software. Starting in commit aa20ef288828b04550950cf67c831af8a525f508 and prior to commit ceacd5f1476458792c44c6a993670f02c984b4a0, authors with at least one submission on a HotCRP site could use the document API

How urgent is CVE-2026-23878?

Priority 29/100. No elevated risk signals yet.

Related CVEs

CVE-2026-23836 CRITICAL 9.9 UPGRADE HotCRP is conference review software

References

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