What is CVE-2013-2251?

CVE-2013-2251 is Apache Struts Improper Input Validation Vulnerability. The supplied enrichment data classifies it as Injection mapped to CWE-74 Injection.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Yes: CISA KEV signal present. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

Yes. The supplied enrichment data lists CVE-2013-2251 in CISA KEV with required action: Apply updates per vendor instructions.. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

118 public PoC repositories reported; 1 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS, database audit logs where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2013-2251 using CVSS 9.8, EPSS 100%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Treat as emergency remediation because CISA KEV status is present. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

CISA KEVcriticalInjectionpublic exploit

CVE-2013-2251

CVE-2013-2251 — Apache Struts Improper Input Validation Vulnerability

Apache Struts 2.0.0 through 2.3.15 allows remote attackers to execute arbitrary OGNL expressions via a parameter with a crafted (1) action:, (2) redirect:, or (3) redirectAction: prefix.

Published Jul 20, 2013Updated Jun 16, 2026Sources: NVD, Apache (CNA), CISA, FIRST EPSS, GitHub, Exploit-DB, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Confirmed

CISA KEV, listed Mar 25, 2022

EPSS

100%

top of FIRST's scoreset

Affects

Apache

Struts

CVSS base

9.8

critical · 2 sources

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

Active

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade Struts to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

CISA required action

Apply updates per vendor instructions.

Federal deadline Apr 15, 2022 — passed 1,613 days ago

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Treat as emergency remediation because CISA KEV status is present.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
Apache	Struts	—	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

High

Confidentiality

High

Integrity

High

Scope

Unchanged

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
9.8	CVSS 3.1	critical	3.9	5.9	NVD, CNA
9.3	CVSS 2.0	high	8.6	10	NVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-20 · Improper Input Validation

DoS: Crash, Exit, or Restart
DoS: Resource Consumption (CPU)
DoS: Resource Consumption (Memory)
Read Memory

Mitigation: Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses. [REF-1109] [REF-1110] [REF-1111]

CWE-74 · Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Read Application Data
Bypass Protection Mechanism
Alter Execution Logic
Other

Mitigation: Programming languages and supporting technologies might be chosen which are not subject to these issues.

Weakness & attack patterns

CWE-74Injection

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-267 · Leverage Alternate EncodingCAPEC-71 · Using Unicode Encoding to Bypass Validation LogicCAPEC-46 · Overflow Variables and TagsCAPEC-83 · XPath InjectionCAPEC-3 · Using Leading 'Ghost' Character Sequences to Bypass Input FiltersCAPEC-273 · HTTP Response SmugglingCAPEC-13 · Subverting Environment Variable ValuesCAPEC-8 · Buffer Overflow in an API CallCAPEC-250 · XML InjectionCAPEC-47 · Buffer Overflow via Parameter ExpansionCAPEC-52 · Embedding NULL BytesCAPEC-42 · MIME Conversion

T1562.003Impair Defenses: Impair Command History Logging
T1574.006Hijack Execution Flow: Dynamic Linker Hijacking
T1574.007Hijack Execution Flow: Path Interception by PATH Environment Variable

CISA KEV details

CISA lists a CVE here once it has evidence of exploitation against real targets.

CISAThat month →

Listed

Mar 25, 2022

Federal deadline

Apr 15, 2022

passed 1,613 days ago

Ransomware use

Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

106

1 of the 5 sampled are weaponized

Exploit entries

Exploit-DB and CTI exploit indexes

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Prioritize edge telemetry for network-reachable Struts.
Monitor for scanner or exploit-pattern traffic after 118 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPSdatabase audit logs

Groups associated with this CVE

Groups reported in connection with this vulnerability. A reported association, not a confirmed observation of that group using it — and not scoped to any sector or campaign.

hash334e32e7eea638089a7259c594d87db965
SOCRadar Threat Exchange Services · Jul 11, 2026
hashb05579c5144602216ce0787cf1161bb60a67e9e265
SOCRadar Threat Exchange Services · Jul 11, 2026
hash49152:deurfqriidw7kamngrs7qibb8gdcdomsu+zomwghvls3uewtzkcfz6gc7ppyziil:c+vq5pmgcpv+
SOCRadar Threat Exchange Services · Jun 29, 2026

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 9.8 (AV:N)
Jun 16, 2026 · NVD
2025
Bulletin released on Mitre.
Jul 28, 2025 · SOCRadar CTI
Bulletin released on NIST.
Feb 7, 2025 · SOCRadar CTI
2024
Bulletin released on NIST.
Jul 16, 2024 · SOCRadar CTI
2023
CVE is exploited. "Ostorlab/KEV"
Dec 26, 2023 · SOCRadar CTI
CVE is exploited. "20142995/pocsuite3"
Dec 16, 2023 · SOCRadar CTI
CVE is exploited. "ARPSyndicate/cvemon"
Dec 15, 2023 · SOCRadar CTI
CVE is exploited. "HimmelAward/Goby_POC"
Dec 15, 2023 · SOCRadar CTI
CVE is exploited. "Ostorlab/known_exploited_vulnerbilities_detectors"
Dec 15, 2023 · SOCRadar CTI
CVE is exploited. "TmmmmmR/PoCs"
Dec 15, 2023 · SOCRadar CTI
CVE is exploited. "fadelmuharam/s2-016"
Dec 15, 2023 · SOCRadar CTI
2022
Added to CISA KEV catalog
Mar 25, 2022 · CISA
2014
Added · Verified webapps entry: Apache Struts2 2.0.0 < 2.3.15 - Prefixed Parameters OGNL Injection
Jan 14, 2014 · Exploit-DB
2013
Added · Verified remote entry: Apache Struts 2 - DefaultActionMapper Prefixes OGNL Code Execution (Metasploit)
Jul 27, 2013 · Exploit-DB
Initial · CVE published
Jul 20, 2013 · NVD

Source activity

Readings a source repeats on a schedule, counted rather than listed.

12×Github ReposApr 19, 2022 – Jan 26, 2024 · SOCRadar CTI
5×ModifiedJul 16, 2024 – Mar 13, 2025 · SOCRadar CTI
1×Tweets · 1 times tweetedDec 22, 2023 · SOCRadar CTI
1×SVRS is calculatedAug 4, 2023 · SOCRadar CTI

References

21 on the record

archiva.apache.org/security.html
Product, NIST, MITRE_REFERENCES
cxsecurity.com/issue/WLB-2014010087
Exploit, Third Party Advisory, NIST, MITRE_REFERENCES, GITHUB
osvdb.org/98445
Broken Link, NIST
packetstormsecurity.com/files/159629/Apache-Struts-2-Remote-Code-Execution.html
Exploit, Third Party Advisory, VDB Entry, NIST, GITHUB
seclists.org/fulldisclosure/2013/Oct/96
Exploit, Mailing List, Third Party Advisory, Mitre, NIST
seclists.org/oss-sec/2014/q1/89
Mailing List, Third Party Advisory, Mitre, NIST
struts.apache.org/release/2.3.x/docs/s2-016.html
Patch, NIST, MITRE_REFERENCES, GITHUB
tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20131023-struts2
Third Party Advisory, Mitre, NIST, GITHUB

Coverage

3 stories from the feeds we poll

Elsewhere on this site

Apacheevery CVE for this vendor
March 2022what else CISA listed
Injectionsame class
CWE-74other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

Only the 3 indicator(s) reported for this CVE are available; no packet-level or host-forensic artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2013-2251 is Apache Struts Improper Input Validation Vulnerability, a critical vulnerability affecting Struts from Apache. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 118 public PoC repositories reported; 1 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 9.8 describes technical severity, while EPSS 100% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.