CVE-2025-29845VulnerabilityPublished 4 Dec 2025

CVE-2025-29845: Synology Router Manager (SRM) · Path Traversal

Affects Synology Router Manager (SRM)Source CVE Database V5

Not known to be exploited · CVSS 4.3 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

4.3Medium

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 37% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within 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 Dec 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 2026-10-25.

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

Affected software

Product	Affected	Fixed in
Synology Synology Router Manager (SRM)	Affected =1.3	Fixed in–

AI-suggested

1. Upgrade Synology Router Manager (SRM) to a version beyond 1.3 where this vulnerability is patched once available. 2. Restrict access to the VideoPlayer2 subtitle CGI interface by implementing network segmentation and firewall rules to limit access only to trusted users and management networks. 3. Enforce strong authentication mechanisms, including multi-factor authentication (MFA), to reduce the risk of credential compromise. 4. Monitor router logs for unusual access patterns to subtitle files or the CGI interface, which could indicate exploitation attempts. 5. Disable or remove unnecessary services or features related to subtitle handling if not required in the deployment environment. 6. Educate users and administrators about the risks of credential theft and encourage regular password updates. 7. Conduct regular vulnerability assessments and penetration testing focusing on router management interfaces to detect similar issues proactively.

Description

A vulnerability in VideoPlayer2 subtitle cgi allows remote authenticated users to read .srt files.

Impact

For European organizations, this vulnerability could lead to unauthorized disclosure of subtitle files stored on Synology routers running SRM 1.3. While subtitle files themselves may seem low risk, they can contain metadata or embedded information that could aid attackers in profiling the network or user behavior. In sensitive environments, such as government, healthcare, or critical infrastructure sectors, any unauthorized file access could be leveraged for further attacks or espionage. The requirement for authentication limits the attack surface but does not eliminate risk, especially if credential compromise occurs through phishing or other means. Additionally, Synology devices are popular in small to medium enterprises and home office setups across Europe, increasing the potential exposure. The vulnerability does not disrupt router functionality or network availability, but the confidentiality breach could have cascading effects depending on the data contained in the subtitle files or the attacker's objectives.

References

synology.com/en-global/security/advisory/Synology_SA_25_04 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Dec 2025, 15:32 UTC

Technical details

References

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