VulnerabilityPublished 4 Nov 2026

CVE-2026-57566: readest · Server-Side Request Forgery

Affects readestSource CVE Database V5

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Not known to be exploited · CVSS 9.3 Critical : upgrade to 0.11.10 as a priority.

Data as of 4 Nov 2026, 22:07 UTC

CVSS 3.1 base score

9.3Critical

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	9.3

Patch: Available – fixed in 0.11.10

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
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: 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: 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 4 Nov 2026
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 4 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 readest and readest/readest to 0.11.10.

Affected software

Product	Affected	Fixed in
readestreadest	Affected <0.11.10	Fixed in 0.11.10
GitHubreadest/readest`pkg:github/readest/readest`Other threats	Affected <0.11.10	Fixed in 0.11.10

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

AI-suggested

Upgrade readest to version 0.11.10 or later, where this SSRF vulnerability is fixed. For cloud-hosted deployments such as Cloudflare Workers, the vendor manages internal network access restrictions, but the unauthenticated fetch-and-reflect behavior remains and should be monitored. No other specific mitigations are indicated by the vendor advisory.

Description

CVE-2026-57566 is a critical server-side request forgery (SSRF) vulnerability in readest versions prior to 0.11.10. The unauthenticated /api/opds/proxy route allowed attackers to supply arbitrary URLs that the server would fetch without proper restrictions or validation. This enabled attackers to use the service as an open proxy to access internal network resources, including cloud metadata services on self-hosted deployments. Cloudflare Workers deployments mitigate internal network impact by restricting access to private and link-local addresses, but the fetch-and-reflect behavior remains unauthenticated. The issue is fixed in version 0.11.10.

Impact

An unauthenticated remote attacker can exploit this SSRF vulnerability to make the readest server fetch arbitrary URLs, potentially accessing sensitive internal network resources or cloud metadata services. This can lead to information disclosure of critical internal infrastructure data. The vulnerability has a CVSS score of 9.3, indicating critical severity with high confidentiality impact and low integrity impact. Cloudflare Workers deployments reduce internal network risk but do not eliminate unauthenticated proxy usage.

Summary

Readest before version 0.11.10 contains an SSRF vulnerability in the unauthenticated /api/opds/proxy route. This route accepts attacker-controlled URLs and fetches them server-side without restricting schemes, blocking private or loopback addresses, or validating redirects. It also accepts caller-controlled outbound headers and Authorization values, reflecting upstream status and response bodies. On self-hosted environments with internal network access, attackers can exploit this to retrieve sensitive internal service responses or cloud metadata. Cloudflare Workers deployments restrict internal network access but do not require authentication for the proxy fetch. The vulnerability is addressed in readest version 0.11.10.

CWE-918Server-Side Request Forgery (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.
Implementation · Operation
If there is a known list of applications, IP, hostname, and/or domains to which the product is allowed to communicate, then use allowlists to ensure that outgoing requests are restricted to these known entities. The allowlists could be in the application code or possibly enforced by firewalls or network segmentation.
Implementation · Operation
If the product is expected to be able to connect to arbitrary IP addresses or domains, consider using a denylist that includes private network addresses, internal domain names, etc. The denylist could be in the application code or possibly enforced by firewalls or network segmentation.
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
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 4 Nov 2026, 21:54 UTC

WeaknessesCWE-918

Technical details

References

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