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🛡️ CVE-2026-61511

🔴 CVSS 9.8 — Critical ✅ No Known Exploit CWE-95 NVD
9.8
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2026-61511 is classified as CWE-95: Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection'). The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes code syntax before using the input in a dynamic evaluation call (e.g. "eval").

Affected software

CVE-2026-61511 is recorded against 1 package.

  • unknown

Timeline and source

Published on 27 July 2026 and last revised on 7 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

forum.vbulletin.com
forum.vbulletin.com
karmainsecurity.com
ssd-disclosure.com
www.vulncheck.com
seclists.org

Other advisories for this package

unknown has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-95: Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')) in other software:

Details

Severity CRITICAL
CVSS Score 9.8
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE CWE-95
Public Exploit ✅ No
Source NVD
Published 2026-07-27
Updated 2026-08-20
Modified 2026-08-07
Fix URL N/A

Affected Packages

Software From version Fixed in
unknown — —

Similar Threats

Exploit Protection

Are you running the affected software?

CVE-2026-61511 carries CVSS 9.8 Critical rating. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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