VulnerabilityPublished 22 Jan 2026

CVE-2026-24117: sigstore rekor · Server-Side Request Forgery (SSRF)

Affects sigstore rekorSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.5.0 when convenient.

Data as of 26 Oct 2026, 10:12 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 29% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.5.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
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: 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: 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 22 Jan 2026
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

Upgrade rekor and sigstore/rekor to 1.5.0.

Affected software

Product	Affected	Fixed in
sigstorerekor	Affected <1.5.0	Fixed in 1.5.0
GitHubsigstore/rekor`pkg:github/sigstore/rekor`Other threats	Affected <1.5.0	Fixed in 1.5.0

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 sigstore rekor to version 1.5.0 or later to remediate this vulnerability. If immediate patching is not feasible, disabling the vulnerable /api/v1/index/retrieve endpoint by setting --enable_retrieve_api=false is strongly recommended to prevent SSRF exploitation. Network-level controls should be implemented to restrict outbound HTTP requests from rekor servers to only trusted destinations, minimizing the risk of SSRF abuse. Additionally, internal network segmentation and monitoring should be enhanced to detect anomalous internal requests originating from the rekor server. Security teams should audit usage logs for unusual access patterns to the retrieve API endpoint and conduct penetration testing to identify potential SSRF exploitation paths. Finally, organizations should incorporate this vulnerability into their risk management and incident response plans, ensuring readiness for potential SSRF-related reconnaissance activities.

Description

CVE-2026-24117 is a Server-Side Request Forgery (SSRF) vulnerability affecting sigstore's rekor component versions 1.4.3 and below. The vulnerability arises because the /api/v1/index/retrieve endpoint allows retrieval of a public key via a user-supplied URL, enabling attackers to send GET requests to arbitrary internal services. Although the SSRF cannot mutate state or exfiltrate data due to the lack of response forwarding, it allows blind probing of internal networks. The issue is fixed in version 1.5.0, and a workaround is to disable the vulnerable endpoint with --enable_retrieve_api=false. The CVSS score is 5.3 (medium severity), reflecting limited impact and ease of exploitation without authentication or user interaction.

Impact

For European organizations using sigstore rekor versions prior to 1.5.0, this SSRF vulnerability poses a risk of internal network reconnaissance by unauthorized actors. Although the vulnerability does not allow direct data theft or service disruption, it can facilitate lateral movement or identification of sensitive internal services, increasing the attack surface for subsequent exploitation. Organizations relying on rekor for software supply chain transparency may face risks to the confidentiality of their internal infrastructure layout. This is particularly relevant for critical infrastructure providers, government agencies, and large enterprises in Europe that adopt sigstore for software integrity verification. The inability to exfiltrate data limits immediate damage, but the reconnaissance capability could aid sophisticated attackers in planning further attacks, especially in environments with weak internal segmentation or insufficient monitoring of internal traffic.

Summary

CVE-2026-24117 is a medium severity SSRF vulnerability in the sigstore rekor software supply chain transparency log, specifically in versions 1.4.3 and earlier. The vulnerability exists in the /api/v1/index/retrieve endpoint, which accepts a user-provided URL to retrieve a public key. This design flaw allows an attacker to induce the server to perform HTTP GET requests to arbitrary internal or external URLs. Because the SSRF only supports GET requests, it cannot alter the state of targeted services, and the server does not relay the response back to the attacker, preventing direct data exfiltration. However, attackers can perform blind SSRF attacks to map internal network topology or identify accessible internal services, which could be leveraged in multi-stage attacks. The vulnerability is classified under CWE-918 (Server-Side Request Forgery). The issue was publicly disclosed on January 22, 2026, and fixed in rekor version 1.5.0. Until patching, disabling the vulnerable retrieve API endpoint using the --enable_retrieve_api=false flag serves as an effective mitigation. No known exploits are currently reported in the wild.

CWE-918Server-Side Request Forgery (SSRF) (opens in a new tab)
Base weaknessCWE Top 25 (2025): #22OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.6.1 (opens in a new tab)
V5.2.6 (opens in a new tab)
Attack patterns
Server Side Request Forgery (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 30 Jan 2026, 10:01 UTC

WeaknessesCWE-918

Technical details

References

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