CVE-2021-25981Network attack vector

Administrator access via reusable logged-out session token

Published Jan 3, 2022 · Updated Aug 3, 2024

Session expiration failure in Talkyard regular 0.2021.20 through 0.2021.33 and dev through 0.2021.34 allows attackers to gain administrator access. The logout path leaves the server-side administrator session valid, so presenting its previously issued token continues to authorize privileged requests. Exploitation requires prior acquisition of an administrator token through a separate attack; token reuse then grants that account's privileges.

CVSS severity9.8
Critical
EPSS probability2.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Session expiration failure in Talkyard regular 0.2021.20 through 0.2021.33 and dev through 0.2021.34 allows attackers to gain administrator access. The logout path leaves the server-side administrator session valid, so presenting its previously issued token continues to authorize privileged requests. Exploitation requires prior acquisition of an administrator token through a separate attack; token reuse then grants that account's privileges.

The record

CVE
CVE-2021-25981
Published
Jan 3, 2022
Updated
Aug 3, 2024
Vendor
Debiki AB
Product
Talkyard
Classifications
CWE-613, T1550.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 3, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=v0.2021.34
  2. Affected versionversion=v0.2021.20 <unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Debiki AB · Talkyardversion=unspecified <=v0.2021.34; version=v0.2021.20 <unspecified

Published CVSS scores

10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8MendCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-613Insufficient Session Expiration
T1550.004Web Session Cookie

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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