Cyber Resilience

CVE-2026-32110

SSRF in B3Log Siyuan ≤ 3.6.0

Public PoCSSRF
Published
11 March 2026
Modified
13 March 2026
Patch / advisory
CVSS Score v3.1 8.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
EPSS Score 0.0028 20th percentile
Risk Priority 60 floored blend · peak EPSS

Summary

CVE-2026-32110 is a high-severity SSRF (CWE-918) vulnerability in B3Log Siyuan. Its CVSS base score is 8.3 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 20th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-32110 is a server-side request forgery (SSRF) vulnerability, classified under CWE-918, affecting SiYuan, an open-source personal knowledge management system. In versions prior to 3.6.0, the `/api/network/forwardProxy` endpoint enables authenticated users to initiate arbitrary HTTP requests from the SiYuan server itself. The endpoint accepts a user-supplied URL without any validation, allowing requests to internal networks, localhost, or cloud metadata services, and returns the full response body and headers to the user.

An attacker with authenticated access to a SiYuan instance (requiring low privileges, PR:L) can exploit this vulnerability remotely over the network (AV:N) with low attack complexity (AC:L) and no user interaction (UI:N). Successful exploitation grants high confidentiality (C:H) and integrity (I:H) impacts, with low availability impact (A:L), yielding a CVSS v3.1 base score of 8.3. Attackers can leverage the server-side requests to access and exfiltrate data from internal services, local resources, or sensitive cloud endpoints like instance metadata, potentially enabling lateral movement or privilege escalation within the victim's infrastructure.

The official GitHub Security Advisory (GHSA-56cv-c5p2-j2wg) confirms the issue and states that it is fully resolved in SiYuan version 3.6.0, recommending immediate upgrades to mitigate the vulnerability. No additional workarounds are detailed in the provided references.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

SiYuan is a personal knowledge management system. Prior to 3.6.0, the /api/network/forwardProxy endpoint allows authenticated users to make arbitrary HTTP requests from the server. The endpoint accepts a user-controlled URL and makes HTTP requests to it, returning the full response…

more

body and headers. There is no URL validation to prevent requests to internal networks, localhost, or cloud metadata services. This vulnerability is fixed in 3.6.0.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-40107Same product: B3Log Siyuan
CVE-2026-23851Same product: B3Log Siyuan
CVE-2026-33194Same product: B3Log Siyuan
CVE-2024-53504Same product: B3Log Siyuan
CVE-2026-25992Same product: B3Log Siyuan
CVE-2025-67488Same product: B3Log Siyuan
CVE-2024-55657Same product: B3Log Siyuan
CVE-2024-55658Same product: B3Log Siyuan
CVE-2026-32747Same product: B3Log Siyuan
CVE-2024-53507Same product: B3Log Siyuan

Affected Assets

b3log
siyuan
≤ 3.6.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V1.3.6
  • V1.5.3
  • V5.3.2
  • V10.4.7

Mitigating Controls (NIST 800-53 r5) AI

Information flow enforcement can restrict which destinations the server is allowed to contact on behalf of users.

Input validation directly stops untrusted URLs from being accepted and fetched without destination checks.

Boundary protection limits the network reach of server-initiated requests even if SSRF occurs.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure development practices directly include input validation and destination allow-listing that prevent SSRF.

DE.CM-09 partial match
prevents

Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover and record SSRF flaws in web applications.

PR.IR-01 partial match
prevents

Network segmentation and egress controls can limit the damage from successful SSRF requests.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.

References