CVE-2026-45077
HIGH 8.3Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, the server:log listener (Symfony\Bridge\Monolog\Command\ServerLogCommand) binds to 0.0.0.0:9911 by default and processes each received frame with unserialize(base64_decode($message)) without authentication, integrity checks, or an allowed_classes allowlist, allowing any reachable host to submit attacker-chosen serialized PHP payloads that can crash the listener and may trigger object-injection gadget effects. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
Severe if exploited (CVSS 8.3), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.4%chance of exploitation in 30 days · 36th percentile
Impact if exploited
8.3CVSS 4.0 · HIGH
- ConfidentialityLow
- IntegrityLow
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
- ⚠Requirements: Specific conditions must be present
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-45077/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-45077/poc.json
Weakness (CWE)
- CWE-502: : Deserialization of Untrusted Data
- CWE-668: : Exposure of Resource to Wrong Sphere
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Sensiolabs | Symfony | < 5.4.52 |
| Sensiolabs | Symfony | ≥ 6.0.0 and < 6.4.40 |
| Sensiolabs | Symfony | ≥ 7.0.0 and < 7.4.12 |
| Sensiolabs | Symfony | ≥ 8.0.0 and < 8.0.12 |
All CVSS metrics
- HIGH 8.3 v4.0 · CNA Primary
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N - HIGH 8.3 v4.0 · NVD Secondary
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/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 - HIGH 8.6 v3.1 · NVD Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H