CVE-2007-4556: Struts support in OpenSymphony XWork before 1.2.3, and 2.x before 2.0.4, as used in WebWork and Apache Struts,

This week

MEDIUM 6.8WATCHLISTUPGRADE

CVE-2007-4556 is a medium-severity flaw (CVSS 6.8) affecting xwork. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Struts support in OpenSymphony XWork before 1.2.3, and 2.x before 2.0.4, as used in WebWork and Apache Struts, recursively evaluates all input as an Object-Graph Navigation Language (OGNL) expression when altSyntax is enabled, which allows remote attackers to cause a denial of service (infinite loop) or execute arbitrary code via form input beginning with a "%{" sequence and ending with a "}" character.

Why this priority

EPSS top 2%: very likely to be exploited
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	6.8 (Medium)
EPSS exploit chance	25.7% (top 2%)
CISA exploited list	No
Published	2007-08-28
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: opensymphony

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2007-08-28 01:17 UTCPublished CVE record published
2026-06-16 22:44 UTCUpdated Record last modified

opensymphony xwork UPGRADE

Affected: < 1.2.3 · >= 2.0.0 and <= 2.0.4

Fixed in: 1.2.3

Safe to downgrade to: a release before 2.0.0

1. Check installed version

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

2. UPGRADE to 1.2.3 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade xwork

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 2.0.0 (Debian / Ubuntu)

apt-cache madison xwork sudo apt install xwork=<VERSION_BEFORE_2.0.0> sudo apt-mark hold xwork

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

dnf --showduplicates list xwork sudo dnf downgrade xwork-<VERSION_BEFORE_2.0.0> sudo dnf versionlock add xwork

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.

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: OpenSymphony XWork/Apache Struts2 - Remote Code Execution

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-2007-4556?

xwork: upgrade to 1.2.3. Exact commands for each OS are on this page.

Is CVE-2007-4556 being exploited?

CVE-2007-4556 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-2007-4556 affect?

CVE-2007-4556 affects xwork. Severity is medium (CVSS 6.8). Struts support in OpenSymphony XWork before 1.2.3, and 2.x before 2.0.4, as used in WebWork and Apache Struts, recursively evaluates all input as an Object-Graph Navigation Language (OGNL) expression when altSyntax is enabled, which allows

How urgent is CVE-2007-4556?

Priority 53/100. EPSS top 2%: very likely to be exploited; On your watchlist

Software pages

Apache Struts vulnerabilities

Related CVEs

CVE-2011-2088 MEDIUM 5.0 DOWNGRADE DOWNGRADE XWork 2.2.1 in Apache Struts 2.2.1, and OpenSymphony XWork in OpenSymphony WebWork, allows remote attackers to
CVE-2011-1772 LOW 2.6 DOWNGRADE MITIGATE Multiple cross-site scripting (XSS) vulnerabilities in XWork in Apache Struts 2.x before 2.2.3, and OpenSympho
CVE-2008-6504 MEDIUM 5.0 DOWNGRADE DOWNGRADE ParametersInterceptor in OpenSymphony XWork 2.0.x before 2.0.6 and 2.1.x before 2.1.2, as used in Apache Strut

References

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