CVE-2026-1691Public exploitNetwork attack vector

Authenticated code execution via unsafe YAML loading

Published Jan 30, 2026 · Updated Jan 30, 2026

Deserialization in Bolo-Solo 2.6.0 through 2.6.4 allows remote authenticated users to execute code via a crafted Markdown archive. The importMarkdownsSync path passes Markdown content from an uploaded archive to parseArticle, which invokes SnakeYAML without a safe loader and instantiates attacker-selected Java types. Authenticated access to the Markdown import function is required; a crafted YAML tag can load a remote JAR and execute code in the server process.

CVSS severity6.3
Medium
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization in Bolo-Solo 2.6.0 through 2.6.4 allows remote authenticated users to execute code via a crafted Markdown archive. The importMarkdownsSync path passes Markdown content from an uploaded archive to parseArticle, which invokes SnakeYAML without a safe loader and instantiates attacker-selected Java types. Authenticated access to the Markdown import function is required; a crafted YAML tag can load a remote JAR and execute code in the server process.

The record

CVE
CVE-2026-1691
Published
Jan 30, 2026
Updated
Jan 30, 2026
Vendor
bolo-blog
Product
Bolo-Solo
Classifications
CWE-20, CWE-502, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.6.0
  2. Affected versionversion=2.6.1
  3. Affected versionversion=2.6.2
  4. Affected versionversion=2.6.3
  5. Affected versionversion=2.6.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

bolo-blog · Bolo-Soloversion=2.6.0; version=2.6.1; version=2.6.2; version=2.6.3; version=2.6.4

Published CVSS scores

6.5VulDBAV:N/AC:L/Au:S/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.3VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
2.1VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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