CVE-2025-64484VulnerabilityPublished 12 Nov 2025Updated 17 Nov 2025

github.com/oauth2-proxy/oauth2-proxy/v7 · V7: OAuth2-Proxy is vulnerable to header smuggling via underscore leading to potential privilege escalation

Affects github.com/oauth2-proxy/oauth2-proxy/v7Source GCVE Database

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Authoritative record:CVE-2025-64484· High 8.5

Not known to be exploited · CVSS 8.5 High : upgrade to 7.13.0 soon.

Data as of 14 Nov 2026, 20:43 UTC

CVSS 3.1 base score

8.5High

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	8.5

EPSS: 0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 7.13.0

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

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

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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 14 Nov 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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

Upgrade github.com/oauth2-proxy/oauth2-proxy/v7 to 7.13.0.

Affected software

Product	Affected	Fixed in
Gogithub.com/oauth2-proxy/oauth2-proxy/v7	Affected <7.13.0	Fixed in 7.13.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade OAuth2 Proxy to version 7.13.0 or later, which includes a fix that normalizes header names to treat underscores and dashes equivalently when stripping headers. If upgrading is not immediately possible, ensure that upstream services do not treat headers with underscores and dashes as equivalent or implement filtering logic that accounts for both forms. The vendor provides a configuration option (InsecureSkipHeaderNormalization) to disable header normalization if there is a specific need to preserve similar-looking headers.

Description

OAuth2 Proxy versions prior to 7.13.0 are vulnerable to a header smuggling issue where authenticated users can bypass header filtering by using underscore variants of X-Forwarded-* headers. This can lead to potential privilege escalation in upstream applications that normalize underscores to dashes in HTTP headers, such as those using WSGI-based frameworks. The vulnerability does not compromise OAuth2 Proxy's authentication or authorization mechanisms. The issue is fixed in version 7.13.0 by normalizing header names to treat underscores and dashes equivalently when stripping headers.

Impact

Authenticated users can exploit this vulnerability to inject headers that bypass OAuth2 Proxy's filtering, potentially escalating privileges in upstream applications that normalize underscores to dashes in HTTP headers. OAuth2 Proxy's own authentication and authorization are not compromised. The impact is limited to privilege escalation in the upstream app due to header smuggling.

Summary

OAuth2 Proxy before version 7.13.0 allows authenticated users to inject HTTP headers with underscores in place of dashes (e.g., X_Forwarded_For) that bypass the proxy's header stripping logic. This occurs because some upstream applications normalize underscores to dashes in headers, causing the proxy to miss these variants and potentially allowing privilege escalation in the upstream app. The vulnerability is addressed in version 7.13.0 by normalizing header names to ignore capitalization and underscore/dash differences when matching headers to be stripped. A configuration option is provided to disable this normalization if needed.

CWE-644Improper Neutralization of HTTP Headers for Scripting Syntax (opens in a new tab)
Variant weaknessLikelihood of exploit: HighOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes web scripting syntax in HTTP headers that can be used by web browser components that can process raw headers, such as Flash.
Architecture and Design
Carefully control data that is being placed both in HTTP response headers and in the HTTP response body to ensure that no scripting syntax is present, taking various encodings into account.
Architecture and Design
Disable script execution functionality in the clients' browser.
OWASP Cheat Sheets
Content Security Policy (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
Query Parameterization (opens in a new tab)
OWASP ASVS 4.0.3
V14.4.6 (opens in a new tab)
V14.4.4 (opens in a new tab)
V14.4.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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What to do

Affected software

Description

AI analysisMachine-generated, updated 13 Nov 2026, 19:46 UTC

WeaknessesCWE-644

Technical details

References

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