What is CVE-2026-77131?

CVE-2026-77131 is Cleartext Transmission of Sensitive Information in extension "SYSSY - TYPO3 Monitoring & Security Checks" (syssy). The supplied enrichment data classifies it as Info Disclosure mapped to CWE-319 CWE-319.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Active exploitation is not confirmed from current sources for CVE-2026-77131. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-77131 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

1 public PoC repositories reported; 0 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-77131 using CVSS 5.3, EPSS 0%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Prioritize based on EPSS, PoC availability, and external exposure. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

mediumInfo Disclosurepublic exploit

CVE-2026-77131

CVE-2026-77131 — Cleartext Transmission of Sensitive Information in extension "SYSSY - TYPO3 Monitoring & Security Checks" (syssy)

When OpenSSL is unavailable on the server, the extension transmits TYPO3 system information in cleartext instead of encrypting it. Exploitation requires the attacker to already be in control of the SYSSY project's API key.

Published Aug 25, 2026Updated Aug 25, 2026Sources: NVD, TYPO3 (CNA), GitHub, GitHub Security Advisory, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Exploit code

public exploit, none observed

EPSS

ahead of 0% of scored CVEs

Affects

TYPO3

Extension "SYSSY - TYPO3 Monitoring & Security Checks"

CVSS base

5.3

medium

Remediation

The vendor's own words where we have them.

Upgrade Extension "SYSSY - TYPO3 Monitoring & Security Checks" to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Prioritize based on EPSS, PoC availability, and external exposure.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
TYPO3	Extension "SYSSY - TYPO3 Monitoring & Security Checks"	0 to < 3.0.6	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack Complexity

Low

Attack Vector

Network

Privileges Req

Low

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
5.3	CVSS 4.0	medium	—	—	TYPO3 (CNA)

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-319 · Cleartext Transmission of Sensitive Information

Read Application Data
Modify Files or Directories

Mitigation: Encrypt the data with a reliable encryption scheme before transmitting.

Weakness & attack patterns

CWE-319

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-477 · Signature Spoofing by Mixing Signed and Unsigned ContentCAPEC-383 · Harvesting Information via API Event MonitoringCAPEC-65 · Sniff Application CodeCAPEC-102 · Session SidejackingCAPEC-117 · Interception

T1056.004Input Capture: Credential API Hooking
T1040Network Sniffing

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Prioritize edge telemetry for network-reachable Extension "SYSSY - TYPO3 Monitoring & Security Checks".
Monitor for scanner or exploit-pattern traffic after 1 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 5.3 (AV:N)
Aug 25, 2026 · NVD
Initial · CVE published
Aug 25, 2026 · NVD
Added · GHSA-8j7q-247m-7f82 published (medium)
Aug 25, 2026 · GitHub Security Advisory

References

3 on the record

typo3.org/security/advisory/typo3-ext-sa-2026-015
Vendor Advisory
nvd.nist.gov/vuln/detail/CVE-2026-77131
NVD
github.com/advisories/GHSA-8j7q-247m-7f82
Exploit, Third Party Advisory

Elsewhere on this site

TYPO3every CVE for this vendor
Info Disclosuresame class
CWE-319other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-77131 is Cleartext Transmission of Sensitive Information in extension "SYSSY - TYPO3 Monitoring & Security Checks" (syssy), a medium vulnerability affecting Extension "SYSSY - TYPO3 Monitoring & Security Checks" from TYPO3. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-77131. Public exploit evidence is: 1 public PoC repositories reported; 0 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 5.3 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.