CVE-2025-56266: A Host Header Injection vulnerability in Avigilon ACM v7.10.0.20 allows attackers to execute arbitrary code vi

This week

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2025-56266 is a critical-severity flaw (CVSS 9.8) affecting access control manager. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A Host Header Injection vulnerability in Avigilon ACM v7.10.0.20 allows attackers to execute arbitrary code via supplying a crafted URL.

Why this priority

Critical severity
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.9% (top 13%)
CISA exploited list	No
Weakness	CWE-74, CWE-116, CWE-444
Published	2025-09-08
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: avigilon

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-09-08 18:15 UTCPublished CVE record published
2026-06-17 09:42 UTCUpdated Record last modified

avigilon access control manager DOWNGRADE

Affected: 7.10.0.20

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.10.0.20

1. Check installed version

apt-cache policy access-control-manager || rpm -q access-control-manager || access-control-manager --version

2. No fixed release: DOWNGRADE to a release before 7.10.0.20 (Debian / Ubuntu)

apt-cache madison access-control-manager sudo apt install access-control-manager=<VERSION_BEFORE_7.10.0.20> sudo apt-mark hold access-control-manager

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list access-control-manager sudo dnf downgrade access-control-manager-<VERSION_BEFORE_7.10.0.20> sudo dnf versionlock add access-control-manager

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · pipx · FIXED · 1.18.9-1.fc46 · FEDORA-2026-95305954ab · source

sudo dnf upgrade --advisory=FEDORA-2026-95305954ab

Fedora ELN · libisds · FIXED · 0.11.2-19.eln159 · FEDORA-2026-bf61b68668 · source

sudo dnf upgrade --advisory=FEDORA-2026-bf61b68668

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Nuclei scan template: Avigilon ACM - Host Header Injection

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-56266?

access control manager: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-56266 being exploited?

CVE-2025-56266 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-56266 affect?

CVE-2025-56266 affects access control manager. Severity is critical (CVSS 9.8). A Host Header Injection vulnerability in Avigilon ACM v7.10.0.20 allows attackers to execute arbitrary code via supplying a crafted URL.

How urgent is CVE-2025-56266?

Priority 69/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-56267 CRITICAL 9.8 DOWNGRADE A CSV injection vulnerability in the /id_profiles endpoint of Avigilon ACM v7.10.0.20 allows attackers to exec

References

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