HKUDS nanobot ExecTool shell.py ExecTool._spawn incomplete blacklist

published 2026-09-14 55 d ago modified 2026-09-14 55 d ago also EUVD-2026-77768

cvss: 6.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits: 0; none known

A vulnerability was determined in HKUDS nanobot up to 0.2.1. Impacted is the function ExecTool._guard_command/ExecTool._spawn of the file nanobot/agent/tools/shell.py of the component ExecTool. This manipulation causes incomplete blacklist. It is possible to initiate the attack remotely. Patch name: af582246f141311d574551b7571a517bcc3df750. Applying a patch is the recommended action to fix this issue.

Patch / fix

links 2

github.com/HKUDS/nanobot@af58224 commit
github.com/HKUDS/nanobot#5345 pull request

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 55 d ago (2026-09-14)

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/HKUDS/nanobot/issues/5305 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	5.3	CVSS: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:X
CNA	3.1	6.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:X/RL:O/RC:C
CNA	3.0	6.3	CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:X/RL:O/RC:C
CNA	2.0	6.5	AV:N/AC:L/Au:S/C:P/I:P/A:P/E:ND/RL:OF/RC:C
CNA	4.0	5.3	CVSS: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:X/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
NVD	3.1	6.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
CNA	2.0	6.5	AV:N/AC:L/Au:S/C:P/I:P/A:P

Affected products

HKUDS nanobot

Classification

Weakness

CWE-184 Incomplete List of Disallowed Inputs
CWE-183 Permissive List of Allowed Inputs

References

github.com /HKUDS/nanobot/pull/5345
issue-tracking, patch
github.com /HKUDS/nanobot/commit/af582246f141311d574551b7571a517bcc3df750
patch
github.com /HKUDS/nanobot/issues/5305
issue-tracking, exploit
vuldb.com /vuln/403310
vdb-entry, technical-description
vuldb.com /vuln/403310/cti
signature, permissions-required
vuldb.com /cve/CVE-2026-90808
third-party-advisory
vuldb.com /submit/922849
third-party-advisory
github.com /HKUDS/nanobot/
product

Sources

CVE List CVE-2026-90808
NVD CVE-2026-90808

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary