CVE-2025-46339VulnerabilityPublished 4 Jun 2025

CVE-2025-46339: FreshRSS · Acceptance of Extraneous Untrusted Data With Trusted Data

Affects FreshRSSSource CVE Database V5

Not known to be exploited · CVSS 4.3 Medium : upgrade to 1.26.2 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

4.3Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.26.2

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
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: 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: 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 4 Jun 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 2026-10-26.

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 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 freshrss/FreshRSS to 1.26.2.

Affected software

Product	Affected	Fixed in
GitHubfreshrss/FreshRSS`pkg:github/freshrss/FreshRSS`Other threats	Affected <1.26.2	Fixed in 1.26.2

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

AI-suggested

European organizations should promptly upgrade all FreshRSS instances to version 1.26.2 or later to ensure the favicon hash computation includes proxy parameters, eliminating the favicon poisoning vector. Additionally, organizations should enforce strict proxy configurations with SSL verification enabled to prevent interception or manipulation of feed responses. Network-level protections such as TLS inspection and proxy hardening can reduce the risk of man-in-the-middle attacks. Monitoring feed favicon changes and implementing alerting on unexpected favicon modifications can help detect exploitation attempts. Where feasible, restricting feed sources to trusted domains and validating feed content integrity can further mitigate risks. Finally, educating users about the potential for favicon spoofing and encouraging vigilance when interacting with feed content can reduce social engineering risks.

Description

FreshRSS is a self-hosted RSS feed aggregator. Prior to version 1.26.2, it's possible to poison feed favicons by adding a given URL as a feed with the proxy set to an attacker-controlled one and disabled SSL verifying. The favicon hash is computed by hashing the feed URL and the salt, whilst not including the following variables: proxy address, proxy protocol, and whether SSL should be verified. Therefore it's possible to poison a favicon of a given feed by simply intercepting the response of the feed, and changing the website URL to one where a threat actor controls the feed favicon. Feed favicons can be replaced for all users by anyone. Version 1.26.2 fixes the issue.

Impact

For European organizations using FreshRSS to aggregate RSS feeds internally or publicly, this vulnerability could undermine trust in feed content presentation by allowing attackers to spoof favicons. Although the core feed content is not directly altered, favicon poisoning can be leveraged in targeted phishing campaigns or misinformation efforts by visually associating malicious feeds with trusted sources. This may lead to decreased user confidence, potential exposure to malicious links if users are deceived, and reputational damage. Organizations relying on FreshRSS for critical information dissemination or monitoring could face operational disruptions if users ignore or mistrust feed updates due to altered favicons. However, since the vulnerability does not allow direct code execution or data exfiltration, the impact is primarily on integrity and user perception rather than confidentiality or availability.

Summary

CVE-2025-46339 is a medium-severity vulnerability affecting FreshRSS, a self-hosted RSS feed aggregator, in versions prior to 1.26.2. The vulnerability arises from improper handling of feed favicon URLs when a proxy is used with SSL verification disabled. Specifically, the favicon hash computation only includes the feed URL and a salt but omits critical variables such as the proxy address, proxy protocol, and SSL verification status. This omission allows an attacker who can intercept or control the proxy response to poison the favicon of any feed by substituting the favicon URL with one under their control. Consequently, all users of the affected FreshRSS instance can have their feed favicons replaced with malicious or misleading icons. While this does not directly compromise confidentiality or availability, it impacts integrity by allowing unauthorized modification of displayed feed icons, potentially facilitating phishing or social engineering attacks by misleading users about the source or authenticity of feeds. The vulnerability requires low privileges (PR:L) but no user interaction (UI:N) and can be exploited remotely over the network (AV:N). The issue was addressed in FreshRSS version 1.26.2 by including the missing proxy-related variables in the favicon hash computation, preventing favicon poisoning via proxy manipulation.

CWE-349Acceptance of Extraneous Untrusted Data With Trusted Data (opens in a new tab)
Base weakness
The product, when processing trusted data, accepts any untrusted data that is also included with the trusted data, treating the untrusted data as if it were trusted.
OWASP Cheat Sheets
XML Security (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
REST Assessment (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.2 (opens in a new tab)
V3.5.3 (opens in a new tab)
V13.2.6 (opens in a new tab)
Attack patterns
Cache Poisoning (opens in a new tab)
DNS Cache Poisoning (opens in a new tab)
Manipulating Writeable Configuration Files (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 7 Jul 2025, 02:42 UTC

WeaknessesCWE-349

Technical details

References

Community reviews

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