CVE-2024-28861: Symfony 1 is a community-driven fork of the 1.x branch of Symfony, a PHP framework for web projects

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2024-28861 is a critical-severity flaw (CVSS 9.8) affecting symfony1. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Symfony 1 is a community-driven fork of the 1.x branch of Symfony, a PHP framework for web projects. Starting in version 1.1.0 and prior to version 1.5.19, Symfony 1 has a gadget chain due to dangerous deserialization in `sfNamespacedParameterHolder` class that would enable an attacker to get remote code execution if a developer deserializes user input in their project. Version 1.5.19 contains a patch for the issue.

Why this priority

Critical severity
Public exploit reference
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	1.5% (top 25%)
CISA exploited list	No
Weakness	CWE-502
Published	2024-03-22
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: friendsofsymfony1

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

Am I affected?

Timeline

2024-03-22 17:15 UTCPublished CVE record published
2026-06-17 07:21 UTCUpdated Record last modified

friendsofsymfony1 symfony1 UPGRADE

Affected: >= 1.1.0 and < 1.5.9

Fixed in: 1.5.9

Safe to downgrade to: a release before 1.1.0

1. Check installed version

apt-cache policy symfony1 || rpm -q symfony1 || symfony1 --version

2. UPGRADE to 1.5.9 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade symfony1

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade symfony1

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.1.0 (Debian / Ubuntu)

apt-cache madison symfony1 sudo apt install symfony1=<VERSION_BEFORE_1.1.0> sudo apt-mark hold symfony1

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list symfony1 sudo dnf downgrade symfony1-<VERSION_BEFORE_1.1.0> sudo dnf versionlock add symfony1

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.

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-2024-28861?

symfony1: upgrade to 1.5.9. Exact commands for each OS are on this page.

Is CVE-2024-28861 being exploited?

CVE-2024-28861 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-2024-28861 affect?

CVE-2024-28861 affects symfony1. Severity is critical (CVSS 9.8). Symfony 1 is a community-driven fork of the 1.x branch of Symfony, a PHP framework for web projects. Starting in version 1.1.0 and prior to version 1.5.19, Symfony 1 has a gadget chain due to dangerous deserialization in `sfNamespacedParame

How urgent is CVE-2024-28861?

Priority 63/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

Related CVEs

CVE-2024-28859 MEDIUM 5.0 UPGRADE Symfony1 is a community fork of symfony 1.4 with DIC, form enhancements, latest Swiftmailer, better performanc

References

← Back to latest CVEs