CVE-2021-25980Network attack vector

Account takeover via accepted IP Host header

Published Nov 11, 2021 · Updated Apr 30, 2025

Host header injection in Debiki AB Talkyard allows remote attackers to take over accounts through the password-reset workflow. The site lookup accepted an IPv4 HTTP Host value by routing it to the default site instead of rejecting the unrecognized host. An unauthenticated attacker must lure a victim into clicking a crafted link; the forgot-password flow then permits password reset and account access.

CVSS severity8.8
High
EPSS probability1.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Host header injection in Debiki AB Talkyard allows remote attackers to take over accounts through the password-reset workflow. The site lookup accepted an IPv4 HTTP Host value by routing it to the default site instead of rejecting the unrecognized host. An unauthenticated attacker must lure a victim into clicking a crafted link; the forgot-password flow then permits password reset and account access.

The record

CVE
CVE-2021-25980
Published
Nov 11, 2021
Updated
Apr 30, 2025
Vendor
Debiki AB
Product
Talkyard
Classifications
CWE-74, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Apr 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=tyse-v0.2021.02-879ef3fe1-regular <tyse-v0.2021*
  2. Affected versionversion=v0.04.01 <v0*
  3. Affected versionversion=v0.2020.22-WIP-b2e97fe0e <v0.2020*
  4. Affected versionversion=v0.2021 <=v0.2021.02-WIP-879ef3fe1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Debiki AB · Talkyardversion=tyse-v0.2021.02-879ef3fe1-regular <tyse-v0.2021*; version=v0.04.01 <v0*; version=v0.2020.22-WIP-b2e97fe0e <v0.2020*; version=v0.2021 <=v0.2021.02-WIP-879ef3fe1

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8MendCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

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-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo