high CVSS 7

CVE-2026-7818·Python vulnerability

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.

Severity
high
Software
Python
Fixed in
9.15
Published
2026-05-11

Affected versions

Until: 9.15

Fixed in: 9.15

How to fix this CVE

Upgrade pgAdmin 4 to version 9.15 or later to receive HMAC-based session integrity validation. This patch introduces cryptographic verification of session files before deserialization, preventing arbitrary code execution through malicious session payloads. Organizations running pgAdmin 4 prior to 9.15 should prioritize this update, especially if the sessions directory has misconfigured file permissions or is accessible via other path-traversal vulnerabilities.

sudo dnf update python3-pgadmin4

Defensia detects this vulnerability

How to check if you are affected

  1. Check installed pgAdmin 4 version: python3 -c "import pgadmin; print(pgadmin.__version__)" or check /opt/pgadmin4/web/version.py if deployed from source
  2. Verify session directory permissions: ls -la /var/lib/pgadmin/sessions (look for world-writable or overly-permissive group write access)
  3. Search application logs for deserialization errors: grep -i "pickle\|unmarshal\|deserializ" /var/log/pgadmin/pgadmin4.log
  4. Confirm patch applied by checking for HMAC validation in FileBackedSessionManager: strings $(python3 -c "import pgadmin; print(pgadmin.__file__)") | grep -i "hmac\|sha256"

FAQ

What is CVE-2026-7818?

CVE-2026-7818 is a critical flaw in pgAdmin 4's session handling that deserializes untrusted session files without cryptographic integrity checks. An authenticated attacker with write access to the sessions directory can inject a malicious Python object that executes arbitrary code when the session is loaded.

Is CVE-2026-7818 being actively exploited?

No, CVE-2026-7818 is not currently listed in the CISA Known Exploited Vulnerabilities catalog, and no public exploit code is available. However, the low barrier to exploitation (only requiring sessions directory write access) warrants immediate patching.

What versions of pgAdmin 4 are affected by CVE-2026-7818?

All versions of pgAdmin 4 prior to 9.15 are vulnerable. The vulnerability has been present in the codebase since the FileBackedSessionManager was introduced and affects the entire 4.x release line.

How do I check if my server is vulnerable to CVE-2026-7818?

Run `python3 -c "import pgadmin; print(pgadmin.__version__)"` to check your pgAdmin version. If it returns a version lower than 9.15, your installation is vulnerable.

Does Defensia detect CVE-2026-7818?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Python and pgAdmin 4 are installed on a monitored server, CVE-2026-7818 will appear in your dashboard with remediation steps.

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References

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