VulnerabilityPublished 29 Oct 2025

CVE-2025-10929: Drupal Reverse Proxy Header · Improper Validation of Consistency Within Input

Affects Drupal Reverse Proxy HeaderSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 22% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 29 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Drupal Reverse Proxy Header	Affected =0.0.0	Fixed in–

AI-suggested

Upgrade the Drupal Reverse Proxy Header component to version 1.1.2 or later as soon as the patch is available to address the vulnerability directly.
Implement strict validation and sanitization of HTTP headers at the reverse proxy or load balancer level to prevent malicious or malformed headers from reaching the backend Drupal application.
Configure web application firewalls (WAFs) to detect and block suspicious header manipulations related to reverse proxy headers.
Monitor web server and application logs for unusual patterns in header values or repeated access attempts that could indicate exploitation attempts.
Conduct regular security assessments and penetration testing focusing on reverse proxy configurations and header handling.
Educate system administrators and developers about the risks of improper header validation and enforce secure coding practices.
If immediate patching is not possible, consider temporarily disabling or restricting reverse proxy header processing features until a fix is applied.
Maintain an incident response plan to quickly address any availability issues arising from exploitation attempts.

Description

Improper Validation of Consistency within Input vulnerability in Drupal Reverse Proxy Header allows Manipulating User-Controlled Variables.This issue affects Reverse Proxy Header: from 0.0.0 before 1.1.2.

Impact

For European organizations, the impact of CVE-2025-10929 primarily concerns availability disruptions in web applications using Drupal behind reverse proxies. Many European enterprises, government agencies, and service providers rely on Drupal for content management and web presence. Exploitation could lead to denial of service conditions or erratic application behavior, potentially affecting business continuity and user experience. Although confidentiality and integrity are not directly impacted, availability issues can cause operational downtime, loss of customer trust, and financial consequences. Organizations with critical public-facing websites or services using reverse proxy headers are particularly vulnerable. The lack of required authentication and ease of remote exploitation increase the risk of opportunistic attacks. However, the absence of known exploits in the wild and the medium CVSS score suggest the threat is moderate but should not be ignored. Proactive patching and input validation are essential to mitigate potential disruptions.

CWE-1288Improper Validation of Consistency within Input (opens in a new tab)
Base weakness
The product receives a complex input with multiple elements or fields that must be consistent with each other, but it does not validate or incorrectly validates that the input is actually consistent.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

drupal.org/sa-contrib-2025-111 (opens in a new tab)

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Nov 2025, 02:21 UTC

WeaknessesCWE-1288

Technical details

References

Community reviews

Related threats