Heap-based buffer overflow in the curl_easy_unescape function in lib/escape.c in cURL and libcurl 7.7 through 7.30.0 allows remote attackers
Heap-based buffer overflow in the curl_easy_unescape function in lib/escape.c in cURL and libcurl 7.7 through 7.30.0 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted string ending in a "%" (percent) character.
- Published
- Jul 31, 2013
- Updated
- Jun 16, 2026
- EPSS
- 10.7% · 96th percentile
- CWE
- CWE-119
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Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 27 / 40 · 6.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 3 / 30 · 10.7%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| haxx | curl | cpe:2.3:a:haxx:curl |
| haxx | libcurl | cpe:2.3:a:haxx:libcurl |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| opensuse | opensuse | cpe:2.3:o:opensuse:opensuse |
| redhat | enterprise linux | cpe:2.3:o:redhat:enterprise_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux10.04
- canonical ubuntu linux12.04
- canonical ubuntu linux12.10
- canonical ubuntu linux13.04
- haxx curl7.10
- haxx curl7.10.1
- haxx curl7.10.2
- haxx curl7.10.3
- haxx curl7.10.4
- haxx curl7.10.5
- haxx curl7.10.6
- haxx curl7.10.7
- haxx curl7.10.8
- haxx curl7.11.0
- haxx curl7.11.1
- haxx curl7.11.2
- haxx curl7.12.0
- haxx curl7.12.1
- haxx curl7.12.2
- haxx curl7.12.3
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | curl | before 7.31.0-1 | 7.31.0-1 |
| Debian:6.0 | curl | before 7.21.0-2.1+squeeze4 | 7.21.0-2.1+squeeze4 |
| Debian:7 | curl | before 7.26.0-1+wheezy3 | 7.26.0-1+wheezy3 |
| openSUSE:Tumbleweed | curl | before 7.51.0-1.1 | 7.51.0-1.1 |
| Red Hat:enterprise_linux:5::server | curl | before 0:7.15.5-17.el5_9 | 0:7.15.5-17.el5_9 |
| Red Hat:enterprise_linux:5::server | curl-debuginfo | before 0:7.15.5-17.el5_9 | 0:7.15.5-17.el5_9 |
| Red Hat:enterprise_linux:5::server | curl-devel | before 0:7.15.5-17.el5_9 | 0:7.15.5-17.el5_9 |
| Red Hat:enterprise_linux:6::client | curl | before 0:7.19.7-37.el6_4 | 0:7.19.7-37.el6_4 |
| Red Hat:enterprise_linux:6::client | curl-debuginfo | before 0:7.19.7-37.el6_4 | 0:7.19.7-37.el6_4 |
| Red Hat:enterprise_linux:6::client | libcurl | before 0:7.19.7-37.el6_4 | 0:7.19.7-37.el6_4 |
| Red Hat:enterprise_linux:6::client | libcurl-devel | before 0:7.19.7-37.el6_4 | 0:7.19.7-37.el6_4 |
Same product
haxx: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-22901curl 7.75.0 through 7.76.1 suffers from a use-after-free vulnerability resulting in already freed memory being used when a TLS 1.3 session t50Plan
- CVE-2023-38039When curl retrieves an HTTP response, it stores the incoming headers so that
they can be accessed later via the libcurl headers API.47Plan
- CVE-2024-2398HTTP/2 push headers memory-leak45Plan
- CVE-2019-5482Heap buffer overflow in the TFTP protocol handler in cURL 7.19.4 to 7.65.3.44Plan
- CVE-2017-8817The FTP wildcard function in curl and libcurl before 7.57.0 allows remote attackers to cause a denial of service (out-of-bounds read and app42Plan
- CVE-2017-8816The NTLM authentication feature in curl and libcurl before 7.57.0 on 32-bit platforms allows attackers to cause a denial of service (integer42Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:curl | 7.31.0-1 · Debian:12 | Package registry (OSV) |
| opensuse:curl | 7.51.0-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:curl | 0:7.15.5-17.el5_9 · Red Hat:enterprise_linux:5::server | Package registry (OSV) |
| red hat:curl-debuginfo | 0:7.15.5-17.el5_9 · Red Hat:enterprise_linux:5::server | Package registry (OSV) |
| red hat:curl-devel | 0:7.15.5-17.el5_9 · Red Hat:enterprise_linux:5::server | Package registry (OSV) |
| red hat:libcurl | 0:7.19.7-37.el6_4 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:libcurl-devel | 0:7.19.7-37.el6_4 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
If successful
- Confidentiality
- P · data can be read
- Integrity
- P · data or configuration can be modified
- Availability
- P · the service can be disrupted
- Attack complexity
- M
- Confidentiality impact
- P
- Integrity impact
- P
- Availability impact
- P
Weakness class (CWE)
CWE-119 · Improper Restriction of Operations within the Bounds of a Memory BufferCVSS vector
AV:N/AC:M/Au:N/C:P/I:P/A:P
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Overflow BuffersCAPEC-100likelihood: High · Very High
- Buffer ManipulationCAPEC-123likelihood: High · Very High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
- Filter Failure through Buffer OverflowCAPEC-24likelihood: High · High
- MIME ConversionCAPEC-42likelihood: High · High
- Overflow Binary Resource FileCAPEC-44likelihood: High · Very High
- Buffer Overflow via Symbolic LinksCAPEC-45likelihood: High · High
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
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References
- curl.haxx.se/docs/adv_20130622.html
- lists.opensuse.org/opensuse-updates/2013-07/msg00013.html
- rhn.redhat.com/errata/RHSA-2013-0983.html
- www.debian.org/security/2013/dsa-2713
- www.oracle.com/technetwork/topics/security/cpujul2015-2367936.html
- www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
- www.securityfocus.com/bid/60737
- www.ubuntu.com/usn/USN-1894-1
Vendor advisories and official records. Exploit/PoC links are deliberately left out.