pgAdmin 4: Unsafe deserialization (CWE-502) in file-backed session manager leads to remote code execution

published 2026-05-11 5 mo ago modified 2026-10-26 13 d ago also GHSA-4rhg-h8f2-v4jm , PYSEC-2026-2865 , EUVD-2026-29086

cvss: 7.0; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.1%; EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits: 0; none known

Deserialization of untrusted data (CWE-502) in pgAdmin 4 FileBackedSessionManager.

The session manager performed unsafe deserialization of session-file contents (using Python's standard object-serialization module) before performing any HMAC integrity check. Any file dropped into the sessions directory was deserialized unconditionally. An authenticated user with write access to the sessions directory (whether by misconfiguration or in combination with another path-traversal flaw) could plant a crafted serialized payload to achieve operating-system level remote code execution under the pgAdmin process identity.

Fix prepends a 64-byte hex SHA-256 HMAC over the session body, computed with SECRET_KEY, and verifies it via hmac.compare_digest before any deserialization. The check is raised (rather than asserted) on empty SECRET_KEY so it is not stripped under -O.

This issue affects pgAdmin 4: before 9.15.

Patch / fix

fixed in 2 distros 1 links 2

pypi pgadmin4 9.15
pgadmin.org pgAdmin 4 9.15

pgadmin4 openSUSE Tumbleweed 9.17-1.1

opensuse advisories openSUSE-SU-2026:11508-1

github.com/pgadmin-org/pgadmin4@30a8903 commit
github.com/pgadmin-org/pgadmin4/issues/9901 advisory

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-7818 updated 2026-06-28 cvss 7.0

pgadmin4: unsafe deserialization in file-backed session manager leads to remote code execution

Red Hat All currently supported Red Hat products
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 5 mo ago (2026-05-11)

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.0	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA	4.0	7.3	CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	4.0	7.3	CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/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	7.8	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
GitHub	3.1	7.0	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
OSV	3.1	7.0	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
pypi	pgadmin4	<9.15	9.15

Affected products

pgadmin.org pgAdmin 4

Classification

Weakness

CWE-502 Deserialization of Untrusted Data

References

github.com /pgadmin-org/pgadmin4/issues/9901
issue-tracking, web, patch, vendor-advisory
github.com /pgadmin-org/pgadmin4/commit/30a890337
web
nvd.nist.gov /vuln/detail/CVE-2026-7818
advisory
github.com /pgadmin-org/pgadmin4
package
pypi.org /project/pgadmin4
package
github.com /advisories/GHSA-4rhg-h8f2-v4jm
advisory

Sources

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