The ngx_http_parse_chunked function in http/ngx_http_parse.c in nginx 1.3.9 through 1.4.0 allows remote attackers to cause a denial of service (crash) and execute arbitrary code via a chunked Transfer-Encoding request with a large chunk size, which triggers an integer signedness error and a stack-based buffer overflow.
CVE-2013-2028
“—” beside the score: it is equal to NVD's CVSS v2 base score.
This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 7.5 — NVD rates that HIGH (NVD's v2 bands: LOW 0.0–3.9 / MEDIUM 4.0–6.9 / HIGH 7.0–10.0; no CRITICAL band). Vector AV:N/AC:L/Au:N/C:P/I:P/A:P. CVSS v2 is an older, coarser metric than v3.1/v4.0 (no Scope, no User Interaction, no Attack Requirements), so it is not directly comparable to a v3 or v4 score. NVD has never re-scored this record under v3. EPSS predicts 87% exploitation probability in the next 30 days; it does not lift the v2 base. EPSS sets EG Risk's exploitation input. Confidence: LOW.
Also known asEUVD-2013-2015 (ENISA EUVD) · GHSA-68mc-8233-5xrw (GitHub Security Advisories)Source: ENISA EUVD
- High exploitation likelihood — EPSS 87%
- Public exploit code is available (Metasploit, Exploit-DB, marked verified by Exploit-DB, other public proof-of-concept code)
A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).
- CVSS v2.0 (legacy)
- 7.5HIGHNVD never assigned a CVSS v3 rating to this CVE
- EG Score
- 7.5HIGHlow confidence
- EG Risk
- 69EG Risk 69/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity75% × 45%Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation87% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.Exploitation public PoC (exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high. - EPSS PROB
- 87%
- EPSS %ILE
- 99th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v2.0 · CVSS v2.0AV:N/AC:L/Au:N/C:P/I:P/A:P
- EG Likelihood
- 87% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-29). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track* at medium mission impactTrack at low, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low, Track* at medium and Attend at high mission impact.
A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.
Exploitation public PoC (exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
July 20, 2013
Last Modified
April 29, 2026
References (10)
- secalert@redhat · CVE Programhttp://lists.fedoraproject.org/pipermail/package-announce/2013-May/105176.htmlThird Party Advisory
- secalert@redhat · CVE Programhttp://mailman.nginx.org/pipermail/nginx-announce/2013/000112.htmlMitigation · Patch · Vendor Advisory
- secalert@redhat · CVE Programhttp://nginx.org/download/patch.2013.chunked.txtPatch · Vendor Advisory
- secalert@redhat · CVE Programhttp://packetstormsecurity.com/files/121675/Nginx-1.3.9-1.4.0-Denial-Of-Service.htmlExploit · Third Party Advisory · VDB Entry
- secalert@redhat · CVE Programhttp://secunia.com/advisories/55181 (archived copy: the site no longer serves it)Third Party Advisory
- secalert@redhat · CVE Programhttp://security.gentoo.org/glsa/glsa-201310-04.xmlThird Party Advisory
- secalert@redhat · CVE Programhttp://www.osvdb.org/93037 (archived copy: the site no longer serves it)Broken Link
- secalert@redhat · CVE Programhttp://www.securityfocus.com/bid/59699 (archived copy: the site no longer serves it)Third Party Advisory · VDB Entry
- secalert@redhat · CVE Programhttp://www.vnsecurity.net/2013/05/analysis-of-nginx-cve-2013-2028/Broken Link
- secalert@redhat · CVE Programhttps://github.com/rapid7/metasploit-framework/pull/1834Patch · Third Party Advisory
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 4× in last 7d / 16× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 15 repeat rows among the latest 82 are merged into the row they repeat.
- 2026-10-30 16:27 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-10-29 18:24 UTCEG score recompute
- 2026-10-29 18:24 UTCGHSA enrichmentGHSA-68mc-8233-5xrw · GitHub severity HIGH
- 2026-10-27 16:26 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-10-25 20:09 UTCEG score recompute
- 2026-10-25 16:26 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-10-21 16:26 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-10-19 16:26 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-10-18 11:20 UTCEG score recompute
- 2026-10-14 16:26 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-10-13 16:26 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-10-12 21:25 UTCEG score recompute
- 2026-10-12 16:27 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-10-12 01:32 UTCEG score recompute
- 2026-10-10 19:54 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-10-06 15:10 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-09-30 14:58 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-09-29 20:14 UTCEG score recompute
- 2026-09-24 13:57 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-09-18 19:21 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-09-12 14:55 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-09-11 09:30 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-09-06 13:42 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-09-05 15:22 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-09-04 13:55 UTCEPSS rescoreEPSS 87% · 99th percentile
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- 2026-09-02 14:06 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-08-27 14:20 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-08-26 14:40 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-08-24 07:23 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-08-20 22:50 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-08-19 16:59 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-08-18 13:42 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-08-16 02:09 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-08-08 16:31 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-08-07 16:21 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-07-26 13:47 UTCEG score recomputeAssessed again: 7.5 HIGH
- 2026-07-25 14:12 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-07-23 01:15 UTCGHSA enrichmentGHSA-68mc-8233-5xrw · GitHub severity HIGH
- 2026-07-23 01:13 UTCGHSA enrichmentGHSA-68mc-8233-5xrw · GitHub severity HIGH
- 2026-07-23 01:10 UTCGHSA enrichmentGHSA-68mc-8233-5xrw · GitHub severity HIGH
- 2026-07-23 01:09 UTCEG score recompute▼ 9.00
- 2026-07-23 00:13 UTCEG score recompute
- 2026-07-22 21:51 UTCEG score recompute
- 2026-07-22 14:04 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-07-20 17:03 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-07-16 16:58 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-07-13 22:26 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-07-13 06:08 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-07-04 06:27 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-06-30 23:19 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-06-24 14:02 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-06-23 21:30 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-06-17 17:49 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-06-15 17:44 UTCEPSS rescoreEPSS 87% · 99th percentile
- 2026-06-12 23:08 UTCEPSS rescoreEPSS 93% · 99th percentile
- 2026-06-11 13:56 UTCEPSS rescoreEPSS 93% · 99th percentile
- 2026-06-08 14:14 UTCEPSS rescoreEPSS 93% · 99th percentile
- 2026-06-02 20:10 UTCEPSS rescoreEPSS 93% · 99th percentile
- 2026-05-29 13:41 UTCEPSS rescoreEPSS 93% · 99th percentile
- 2026-05-28 23:13 UTCEG score recompute
- 2026-05-28 23:13 UTCGHSA enrichmentGHSA-68mc-8233-5xrw · GitHub severity HIGH
- 2026-05-28 13:42 UTCEPSS rescoreEPSS 93% · 99th percentile
- 2026-05-27 13:38 UTCEPSS rescoreEPSS 93% · 99th percentile
- 2026-05-26 07:16 UTCEPSS rescoreEPSS 93% · 99th percentile
- 2026-05-20 22:37 UTCEPSS rescoreEPSS 93% · 99th percentile
- 2026-05-20 11:21 UTCEPSS rescoreEPSS 93% · 99th percentile
- 2026-05-18 21:29 UTCEPSS rescoreEPSS 93% · 99th percentile
Publicly available exploits
(9 references)Public exploit code is referenced for this CVE (1 Metasploit module, 4 Exploit-DB entries, 4 GitHub PoCs). No release with the fix is confirmed, so defenders should restrict or isolate affected systems accordingly until one is applied.
- Exploit-DBEDB-25775✓ verifiedPublished May 28, 2013
Nginx 1.3.9 < 1.4.0 - Chuncked Encoding Stack Buffer Overflow (Metasploit)
Open source ↗ - Metasploitexploit/linux/http/nginx_chunked_size✓ verifiedPublished May 22, 2013
Nginx HTTP Server 1.3.9-1.4.0 Chunked Encoding Stack Buffer Overflow
Open source ↗ - GitHub PoCm4drat/CVE-2013-2028-ExploitPublished Jun 27, 2020
CVE-2013-2028 python exploit
Open source ↗ - GitHub PoCtachibana51/CVE-2013-2028-x64-bypass-ssp-and-pie-PoCPublished Aug 3, 2019
this is not stable
Open source ↗ - GitHub PoCkitctf/nginxpwnPublished Mar 23, 2016
Exploitation Training -- CVE-2013-2028: Nginx Stack Based Buffer Overflow
Open source ↗ - Exploit-DBEDB-32277Published Mar 15, 2014
Nginx 1.4.0 (Generic Linux x64) - Remote Overflow
Open source ↗ - Exploit-DBEDB-26737Published Jul 11, 2013
Nginx 1.3.9/1.4.0 (x86) - Brute Force
Open source ↗ - GitHub PoCdanghvu/nginx-1.4.0Published May 21, 2013
For the analysis of CVE-2013-2028
Open source ↗ - Exploit-DBEDB-25499Published May 17, 2013
Nginx 1.3.9 < 1.4.0 - Denial of Service (PoC)
Open source ↗
Related CVEs(same CWE)
Same CWE
10 shownCWE-787
- CVE-2013-4113EG 6.8EPSS p92MEDIUM
- CVE-2013-3163NVD 8.8EG 9.0 KEVEPSS p99CRITICAL
- CVE-2013-2189EG 6.8EPSS p90MEDIUM
- CVE-2013-4156EG 6.8EPSS p90MEDIUM
- CVE-2011-1180EG 9.8CRITICAL
- CVE-2013-3346EG 9.8 KEVEPSS p100CRITICAL
- CVE-2013-1032EG 6.8MEDIUM
- CVE-2013-4365EG 7.5EPSS p96HIGH
- CVE-2013-3918NVD 8.8EG 9.0 KEVEPSS p99CRITICAL
- CVE-2013-5610EG 10.0EPSS p94HIGH
Frequently asked(4)
What is CVE-2013-2028?
When was CVE-2013-2028 made public?
Is CVE-2013-2028 actively exploited?
How do I remediate CVE-2013-2028?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2013-2028
Is Your Infrastructure Affected by CVE-2013-2028?
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