Cyber Resilience

CVE-2026-45077

RCE in Sensiolabs Symfony ≤ 5.4.52

Published
14 July 2026
Modified
15 July 2026
Patch / advisory
CVSS Score v4 8.3
Click a component to see what it means
Raw vectorCVSS: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
EPSS Score 0.0045 37th percentile
Risk Priority 46 floored blend · peak EPSS

Summary

CVE-2026-45077 is a high-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Sensiolabs Symfony. Its CVSS base score is 8.3 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Cloud Instance Metadata API (T1552.005); ranked at the 37th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Symfony 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))…

more

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1552.005 Cloud Instance Metadata API Credential Access
Adversaries may attempt to access the Cloud Instance Metadata API to collect credentials and other sensitive data.
T1552.007 Container API Credential Access
Adversaries may gather credentials via APIs within a containers environment.
T1039 Data from Network Shared Drive Collection
Adversaries may search network shares on computers they have compromised to find files of interest.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1530 Data from Cloud Storage Collection
Adversaries may access data from cloud storage.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-45071Same product: Sensiolabs Symfony
CVE-2026-48784Same product: Sensiolabs Symfony
CVE-2026-48489Same product: Sensiolabs Symfony
CVE-2026-45075Same product: Sensiolabs Symfony
CVE-2026-45069Same product: Sensiolabs Symfony
CVE-2026-48736Same product: Sensiolabs Symfony
CVE-2026-45073Same product: Sensiolabs Symfony
CVE-2026-47767Same product: Sensiolabs Symfony
CVE-2026-45066Same product: Sensiolabs Symfony
CVE-2026-45070Same product: Sensiolabs Symfony

Affected Assets

sensiolabs
symfony
≤ 5.4.52 · 6.0.0 — 6.4.40 · 7.0.0 — 7.4.12

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 8 hardening rules · 7 OS baselines
Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

Access enforcement directly stops resources from being reachable by actors outside the intended control sphere.

Information flow enforcement structurally prevents unintended cross-sphere data or resource exposure.

Least privilege reduces the set of actors that can reach a resource, limiting wrong-sphere exposure.

Developer testing and evaluation can uncover deserialization flaws before deployment.

Input validation directly stops deserialization of untrusted data by ensuring inputs are valid before processing.

Security attributes enable correct sphere assignment and subsequent enforcement decisions.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

Enforcing least-privilege authorizations directly prevents resources from being exposed outside their intended control sphere.

PR.IR-01 partial match
prevents

Network segmentation and unauthorized-access protections reduce the chance of resources being reachable by the wrong sphere.

PR.PS-02 none match
prevents

PR.PS-02 addresses only post-deployment updates/patching and cannot prevent introduction of unsafe deserialization code, yet it can remediate some instances when the flaw exists in outdated libraries or components.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing includes validation of deserialization routines and the use of untrusted data, reducing the likelihood that unsafe object reconstruction will be deployed.

mitigates

Placing systems of differing trust levels into separate domains prevents resources from being placed in a sphere where they are reachable by unintended actors.

prevents

Requiring vetted libraries, regular updates and SAST before release reduces the likelihood that deserialization logic will accept and act on attacker-controlled serialized objects.

finds

Regular scanning of third-party libraries and timely patching reduce the likelihood that unsafe deserialization vulnerabilities remain active.

none

Requiring owners to manage the full asset life cycle and remove assets from the inventory upon secure disposal helps prevent resources from being inadvertently exposed outside their intended security sphere.

none

Mandatory malware scanning of data received over networks or storage media intercepts malicious serialized payloads before they are deserialized by the target application.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-668
  • V-248823 OL 8 must not have the telnet-server package installed. prevents CWE-668
RHEL 7 (1 rule)
  • V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-668
Windows 10 (1 rule)
  • V-220967 The Debug programs user right must only be assigned to the Administrators group. prevents CWE-668
Windows 11 (1 rule)
  • V-253490 The "Debug programs" user right must only be assigned to the Administrators group. prevents CWE-668
Windows Server 2016 (1 rule)
  • V-225079 The Debug programs user right must only be assigned to the Administrators group. prevents CWE-668
Windows Server 2019 (1 rule)
  • V-205757 Windows Server 2019 Debug programs: user right must only be assigned to the Administrators group. prevents CWE-668
Windows Server 2022 (1 rule)
  • V-254500 Windows Server 2022 debug programs user right must only be assigned to the Administrators group. prevents CWE-668

References