CVE-2026-12888

Home/CVE/An HTML injection vulnerability exists in the Google Chat webhook notification sent by Thinkst Applied Research Canary

CVE

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An HTML injection vulnerability exists in the Google Chat webhook notification sent by Thinkst Applied Research Canary

An HTML injection vulnerability exists in the Google Chat webhook notification sent by Thinkst Applied Research Canarytokens, enabling Interface Manipulation in Google Chat. An attacker can insert limited HTML content including links. This issue affects Canarytokens: from Docker tag sha-4aef1db90 before sha-8ab4dccd, from Git commit 4aef1db90 before 8ab4dccd.

Monitor

⚠ NVD has not scored this CVE yet - manual triage required (common for recent CVEs)

No Sigma yet — build one → YARA rules0

Look this up elsewhere - one-click external pivots

NVD CVE.org CISA Exploit-DB GitHub PoC VulnCheck KEV GreyNoise

▸ How to read a CVE - triage first, then detect and patch

This page is every public fact about CVE-2026-12888, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.

Triage: should I act now? Four signals, and they are not interchangeable:

CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.

How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.

Then what - two workflows:

Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.

Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).

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Severity & exploitation scoring

EPSS exploitation probability

n/a

No EPSS score in our data for this CVE. EPSS is published daily for scored CVEs - a very new, reserved, or rejected CVE may not have one yet.

CVSS metric silhouette

No structured CVSS vector for this CVE. Older entries often have only a numeric base score - the metric breakdown radar requires a full AV:_/AC:_/... vector string published by NVD.

SSVC triage · cisa-vulnrichment

Exploitation

none

Automatable

Tech impact

partial

Attack path

Full kill chain

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ATT&CK techniques

Techniques this CVE enables. Pills with a solid outline are high confidence - named directly in ATT&CK or Nuclei, or human-curated by CTID; the rest are inferred from the weakness type using MITRE's CVE Mapping Methodology and the CWE → CAPEC chain. Broad, generic-weakness guesses are filtered out. A small N× marks a technique that N independent sources agree on.

T1027 · Obfuscated Files or Information T1574.006 · Dynamic Linker Hijacking T1574.007 · Path Interception by PATH Environment Variable T1690 · Prevent Command History Logging

▤ Build a SIEM detection for these techniques

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CAPEC attack patterns

Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.

CAPEC-CAPEC-10 · Buffer Overflow via Environment Variables CAPEC-CAPEC-101 · Server Side Include (SSI) Injection CAPEC-CAPEC-105 · HTTP Request Splitting CAPEC-CAPEC-108 · Command Line Execution through SQL Injection CAPEC-CAPEC-120 · Double Encoding CAPEC-CAPEC-13 · Subverting Environment Variable Values CAPEC-CAPEC-135 · Format String Injection CAPEC-CAPEC-14 · Client-side Injection-induced Buffer Overflow CAPEC-CAPEC-24 · Filter Failure through Buffer Overflow CAPEC-CAPEC-250 · XML Injection CAPEC-CAPEC-267 · Leverage Alternate Encoding CAPEC-CAPEC-273 · HTTP Response Smuggling

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Weakness Classification

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

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Related CVEs

CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row. Not a guess.

CVE-2004-2570 Opera before 7.54 allows remote attackers to modify properties and methods of th... same CWE-74 CVE-2004-1157 Opera 7.x up to 7.54, and possibly other versions, allows remote attackers to sp... same CWE-74 CVE-2005-3007 Opera before 8.50 allows remote attackers to spoof the content type of files via... same CWE-74 CVE-2005-3750 Opera before 8.51 on Linux and Unix systems allows remote attackers to execute a... same CWE-74

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References & Sources

Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.

https://github.com/thinkst/canarytokens/security/advisories/GHSA-vcfc-7466-8q65