CVE-2021-25981: In Talkyard, regular versions v0.2021.20 through v0.2021.33 and dev versions v0.2021.20 through v0.2021.34, ar

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2021-25981 is a critical-severity flaw (CVSS 9.8) affecting talkyard. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In Talkyard, regular versions v0.2021.20 through v0.2021.33 and dev versions v0.2021.20 through v0.2021.34, are vulnerable to Insufficient Session Expiration. This may allow an attacker to reuse the admin’s still-valid session token even when logged-out, to gain admin privileges, given the attacker is able to obtain that token (via other, hypothetical attacks)

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.5% (top 15%)
CISA exploited list	No
Weakness	CWE-613
Published	2022-01-03
Last modified	2026-06-17

Publisher (CNA): Mend · Vendor: talkyard

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

Am I affected?

Timeline

2022-01-03 07:15 UTCPublished CVE record published
2026-06-17 03:42 UTCUpdated Record last modified

talkyard talkyard UPGRADE

Affected: >= 0.2021.20 and < 0.2021.35

Fixed in: 0.2021.35

Safe to downgrade to: a release before 0.2021.20

1. Check installed version

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

2. UPGRADE to 0.2021.35 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade talkyard

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 0.2021.20 (Debian / Ubuntu)

apt-cache madison talkyard sudo apt install talkyard=<VERSION_BEFORE_0.2021.20> sudo apt-mark hold talkyard

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

dnf --showduplicates list talkyard sudo dnf downgrade talkyard-<VERSION_BEFORE_0.2021.20> sudo dnf versionlock add talkyard

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-2021-25981?

talkyard: upgrade to 0.2021.35. Exact commands for each OS are on this page.

Is CVE-2021-25981 being exploited?

CVE-2021-25981 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-2021-25981 affect?

CVE-2021-25981 affects talkyard. Severity is critical (CVSS 9.8). In Talkyard, regular versions v0.2021.20 through v0.2021.33 and dev versions v0.2021.20 through v0.2021.34, are vulnerable to Insufficient Session Expiration. This may allow an attacker to reuse the admin’s still-valid session token even wh

How urgent is CVE-2021-25981?

Priority 61/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-25980 HIGH 8.8 UPGRADE In Talkyard, versions v0.04.01 through v0.6.74-WIP-63220cb, v0.2020.22-WIP-b2e97fe0e through v0.2021.02-WIP-87

References

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