What is CVE-2026-61511?

CVE-2026-61511 is vBulletin < 6.2.2 Eval Injection RCE via vb5/template/runtime.php. The supplied enrichment data classifies it as Remote Code Exec mapped to CWE-95 Eval Injection.

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?

Exploitation is reported, but no independent confirmation is available in the sources we have. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-61511 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?

13 public PoC repositories reported; 2 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, EDR process telemetry, host service logs 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-2026-61511 using CVSS 9.8, EPSS 71%, 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.

criticalRemote Code Execpublic exploit

CVE-2026-61511

CVE-2026-61511 — vBulletin < 6.2.2 Eval Injection RCE via vb5/template/runtime.php

Q: 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.

Q: Is there active exploitation?

Exploitation is reported, but no independent confirmation is available in the sources we have. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

Q: Is it in CISA KEV?

No. CVE-2026-61511 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.

Q: Is there a public exploit?

13 public PoC repositories reported; 2 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

Q: How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS, EDR process telemetry, host service logs 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.

Q: How should teams prioritize it?

Prioritize CVE-2026-61511 using CVSS 9.8, EPSS 71%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Q: 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.

Q: 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.

Q: 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.

vBulletin 5.x through 5.7.5 and 6.x through 6.2.1 contains an eval injection vulnerability in the vB5_Template_Runtime::runMaths() method within the template runtime that allows unauthenticated remote attackers to execute arbitrary PHP code by supplying crafted input through the pagenav[pagenumber] parameter. Attackers can exploit the insufficiently restrictive regex filter by using phpfuck-style encoding with permitted characters to inject and execute arbitrary PHP code via the unauthenticated ajax/render template route without any authentication.

Published Jul 27, 2026Updated Aug 7, 2026Sources: NVD, vBulletin (CNA), GitHub, SOCRadar CTI

Triage

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

Exploitation

Reported

not confirmed by CISA

EPSS

71%

ahead of 99.4% of scored CVEs

Affects

vBulletin

3 products listed

CVSS base

9.8

critical · 2 sources

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade vBulletin to a fixed release (6.2.2). 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
vBulletin	vBulletin	5.0.0 to <= 5.7.5	Vulnerable
vBulletin	vBulletin	6.0.0 to <= 6.2.1	Vulnerable
vBulletin	vBulletin	6.2.2	Patched

Attack characteristics

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

Availability

High

Confidentiality

High

Integrity

High

Scope

Unchanged

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

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
9.8	CVSS 3.1	critical	3.9	5.9	VulnCheck (CNA), vBulletin (CNA)
9.3	CVSS 4.0	critical	—	—	vBulletin (CNA)

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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-95 · Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')

Read Files or Directories
Read Application Data
Bypass Protection Mechanism
Gain Privileges or Assume Identity

Mitigation: If possible, refactor your code so that it does not need to use eval() at all.

Weakness & attack patterns

CWE-95Eval Injection

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

CAPEC-35 · Leverage Executable Code in Non-Executable Files

T1027.006Obfuscated Files or Information: HTML Smuggling
T1027.009Obfuscated Files or Information: Embedded Payloads
T1564.009Hide Artifacts: Resource Forking

Public exploit

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

Repositories

2 of the 5 sampled are weaponized

Exploit entries

Exploit-DB and CTI exploit indexes

Social mentions

Posts naming this CVE. Attention, not evidence of exploitation — it spikes on disclosure and decays whether or not anything is exploited.

20 more posts on this CVEShowing 5 of 25 · Who is discussing this CVE, and how loudlyUnlock free

Detection

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

Search application, proxy, and WAF logs for requests touching /render.
Prioritize edge telemetry for network-reachable vBulletin.
Monitor for scanner or exploit-pattern traffic after 13 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPSEDR process telemetryhost service logs

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 9.8 (AV:N)
Aug 7, 2026 · NVD
Cve is exploited tc4dy/CVE-2026-61511-PoC-Exploit
Jul 29, 2026 · SOCRadar CTI
Cve is exploited webshellseo8/CVE-2026-61511-POC
Jul 29, 2026 · SOCRadar CTI
Initial · CVE published
Jul 27, 2026 · NVD

Source activity

Readings a source repeats on a schedule, counted rather than listed.

11×SvrsJul 28, 2026 – Aug 29, 2026 · SOCRadar CTI
9×TweetsJul 28, 2026 – Aug 14, 2026 · SOCRadar CTI
6×Github ReposJul 28, 2026 – Jul 30, 2026 · SOCRadar CTI
3×CVE modified by MITRE: CVSS metrics updated.Jul 27, 2026 – Jul 29, 2026 · SOCRadar CTI
2×1 time mentioned on 1 Telegram channelJul 28, 2026 – Jul 31, 2026 · SOCRadar CTI
1×CVE appeared in the Cve Trends.Jul 28, 2026 · SOCRadar CTI

References

6 on the record

forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-announcements_aa/4509358-security-patch-released-for-vbulletin-6-2-1-6-2-0-and-6-1-6
Vendor Advisory
forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-announcements_aa/4509404-vbulletin-6-2-2-is-available
Vendor Advisory
karmainsecurity.com/KIS-2026-13
Vendor Advisory, NIST, Mitre, GITHUB
ssd-disclosure.com/vbulletin-runtime-template-runmaths-preauth-rce/
Vendor Advisory, NIST, Mitre
www.vulncheck.com/advisories/vbulletin-eval-injection-rce-via-vb5-template-runtime-php
Vendor Advisory, NIST
seclists.org/fulldisclosure/2026/Aug/29
Vendor Advisory, NIST

Coverage

16 stories from the feeds we poll

11 more reports on this CVEShowing 5 of 16 · Vendor research and security press coverageUnlock free

Elsewhere on this site

vBulletinevery CVE for this vendor
Remote Code Execsame class
CWE-95other 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-2026-61511 is vBulletin < 6.2.2 Eval Injection RCE via vb5/template/runtime.php, a critical vulnerability affecting vBulletin from vBulletin. The current evidence does not list it in CISA KEV, and the exploit status is: Exploitation is reported, but no independent confirmation is available in the sources we have. Public exploit evidence is: 13 public PoC repositories reported; 2 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 9.8 describes technical severity, while EPSS 71% 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.