CVE-2026-23850
published 2026-01-19CVE-2026-23850: SiYuan is a personal knowledge management system. In versions prior to 3.5.4, the markdown feature allows unrestricted server side html-rendering which allows…
PriorityP350high7.5CVSS 3.1
AVNACLPRNUINSUCHINAN
EPSS
0.52%
40.3th percentile
SiYuan is a personal knowledge management system. In versions prior to 3.5.4, the markdown feature allows unrestricted server side html-rendering which allows arbitrary file read (LFD). Version 3.5.4 fixes the issue.
Affected
3 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| b3log | siyuan | < 3.5.4 | 3.5.4 |
| github.com | siyuan-note_siyuan_kernel | >= 0 < 0.0.0-20260118092326-b2274baba2e1 | 0.0.0-20260118092326-b2274baba2e1 |
| siyuan-note | siyuan | < 3.5.4 | 3.5.4 |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
nvdv4.07.8HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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OSV
SiYuan vulnerable to Arbitrary file Read / SSRF in github.com/siyuan-note/siyuan/kernel
osv·2026-02-03
CVE-2026-23850 SiYuan vulnerable to Arbitrary file Read / SSRF in github.com/siyuan-note/siyuan/kernel
SiYuan vulnerable to Arbitrary file Read / SSRF in github.com/siyuan-note/siyuan/kernel
SiYuan vulnerable to Arbitrary file Read / SSRF in github.com/siyuan-note/siyuan/kernel
OSV
SiYuan vulnerable to Arbitrary file Read / SSRF
osv·2026-01-21
CVE-2026-23850 [HIGH] SiYuan vulnerable to Arbitrary file Read / SSRF
SiYuan vulnerable to Arbitrary file Read / SSRF
### Summary
Markdown feature allows unrestricted server side html-rendering which allows arbitary file read (LFD) and fully SSRF access
We in @0xL4ugh ( @abdoghazy2015, @xtromera, @A-z4ki, @ZeyadZonkorany and @KarimTantawey) During playing Null CTF 2025 that helps us solved a challenge with unintended way : )
Please note that we used the latest Version and deployed it via this dockerfile :
Dockerfile:
```
FROM b3log/siyuan
ENV TZ=America/New_York \
PUID=1000 \
PGID=1000 \
SIYUAN_ACCESS_AUTH_CODE=SuperSecretPassword
RUN mkdir -p /siyuan/workspace
COPY ./startup.sh /opt/siyuan/startup.sh
RUN chmod +x /opt/siyuan/startup.sh
EXPOSE 6806
ENTRYPOINT ["sh", "-c", "/opt/siyuan/startup.sh"]
```
startup.sh
```sh
#!/bin/sh
set -e
echo "nullctf{
GHSA
SiYuan vulnerable to Arbitrary file Read / SSRF
ghsa·2026-01-21
CVE-2026-23850 [HIGH] CWE-22 SiYuan vulnerable to Arbitrary file Read / SSRF
SiYuan vulnerable to Arbitrary file Read / SSRF
### Summary
Markdown feature allows unrestricted server side html-rendering which allows arbitary file read (LFD) and fully SSRF access
We in @0xL4ugh ( @abdoghazy2015, @xtromera, @A-z4ki, @ZeyadZonkorany and @KarimTantawey) During playing Null CTF 2025 that helps us solved a challenge with unintended way : )
Please note that we used the latest Version and deployed it via this dockerfile :
Dockerfile:
```
FROM b3log/siyuan
ENV TZ=America/New_York \
PUID=1000 \
PGID=1000 \
SIYUAN_ACCESS_AUTH_CODE=SuperSecretPassword
RUN mkdir -p /siyuan/workspace
COPY ./startup.sh /opt/siyuan/startup.sh
RUN chmod +x /opt/siyuan/startup.sh
EXPOSE 6806
ENTRYPOINT ["sh", "-c", "/opt/siyuan/startup.sh"]
```
startup.sh
```sh
#!/bin/sh
set -e
echo "nullctf{
No detection rules found.
No public exploits indexed.
https://github.com/siyuan-note/siyuan/blob/master/kernel/model/file.go#L1035https://github.com/siyuan-note/siyuan/blob/v3.4.2/kernel/api/filetree.go#L799-L886https://github.com/siyuan-note/siyuan/commit/b2274baba2e11c8cf8901b0c5c871e5b27f1f6ddhttps://github.com/siyuan-note/siyuan/commit/f8f4b517077b92c90c0d7b51ac11be1b34b273adhttps://github.com/siyuan-note/siyuan/issues/16860https://github.com/siyuan-note/siyuan/security/advisories/GHSA-cv54-7wv7-qxcw
2026-01-19
Published