CVE-2023-38545: This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake.
Noroxi assessment
Priority: This week (action score 63/100)
- Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
- Probability of exploitation in the next 30 days: 78.6% (FIRST EPSS); higher than 99.5% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: curl curl 8.4.0.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Don’t wait for the next maintenance window. Upgrade to curl curl 8.4.0 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to pass along the host name to the SOCKS5 proxy to allow that to resolve the address instead of it getting done by curl itself, the maximum length that host name can be is 255 bytes. If the host name is detected to be longer, curl switches to local name resolving and instead passes on the resolved address only. Due to this bug, the local variable that means "let the host resolve the name" could get the wrong value during a slow SOCKS5 handshake, and contrary to the intention, copy the too long host name to the target buffer instead of copying just the resolved address there. The target buffer being a heap based buffer, and the host name coming from the URL that curl has been told to operate with.
- Published
- Oct 18, 2023
- Updated
- Jul 14, 2026
- EPSS
- 78.6% · 99th percentile
- CWE
- CWE-787
Report tools
Action score
63
This week
Don’t wait for the next maintenance window.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 24 / 30 · 78.6%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- Proof of concept exists, no weaponized module
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| haxx | libcurl | cpe:2.3:a:haxx:libcurl |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| netapp | active iq unified manager | cpe:2.3:a:netapp:active_iq_unified_manager |
| netapp | oncommand insight | cpe:2.3:a:netapp:oncommand_insight |
| netapp | oncommand workflow automation | cpe:2.3:a:netapp:oncommand_workflow_automation |
| microsoft | windows 10 1809 | cpe:2.3:o:microsoft:windows_10_1809 |
| microsoft | windows 10 21h2 | cpe:2.3:o:microsoft:windows_10_21h2 |
| microsoft | windows 10 22h2 | cpe:2.3:o:microsoft:windows_10_22h2 |
| microsoft | windows 11 21h2 | cpe:2.3:o:microsoft:windows_11_21h2 |
| microsoft | windows 11 22h2 | cpe:2.3:o:microsoft:windows_11_22h2 |
| microsoft | windows 11 23h2 | cpe:2.3:o:microsoft:windows_11_23h2 |
| microsoft | windows server 2019 | cpe:2.3:o:microsoft:windows_server_2019 |
and 1 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- microsoft windows server 2019before 10.0.17763.5122
- microsoft windows server 2022before 10.0.20348.2113
Versions reported by the vendor
Affected version ranges reported by the assigning authority (hackerone). Independent of NVD's CPE analysis and usually ahead of it.
curl curl
- 8.4.0 and later · before 8.4.0affected · semver
- 7.69.0 and later · before 7.69.0not affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:9 | curl | before 7.76.1-26.el9_3.2 | 7.76.1-26.el9_3.2 |
| AlmaLinux:9 | curl | before 7.76.1-23.el9_2.4 | 7.76.1-23.el9_2.4 |
| AlmaLinux:9 | curl-minimal | before 7.76.1-23.el9_2.4 | 7.76.1-23.el9_2.4 |
| AlmaLinux:9 | curl-minimal | before 7.76.1-26.el9_3.2 | 7.76.1-26.el9_3.2 |
| AlmaLinux:9 | libcurl | before 7.76.1-26.el9_3.2 | 7.76.1-26.el9_3.2 |
| AlmaLinux:9 | libcurl | before 7.76.1-23.el9_2.4 | 7.76.1-23.el9_2.4 |
| AlmaLinux:9 | libcurl-devel | before 7.76.1-26.el9_3.2 | 7.76.1-26.el9_3.2 |
| AlmaLinux:9 | libcurl-devel | before 7.76.1-23.el9_2.4 | 7.76.1-23.el9_2.4 |
| AlmaLinux:9 | libcurl-minimal | before 7.76.1-23.el9_2.4 | 7.76.1-23.el9_2.4 |
| AlmaLinux:9 | libcurl-minimal | before 7.76.1-26.el9_3.2 | 7.76.1-26.el9_3.2 |
| Alpine:v3.15 | curl | before 8.4.0-r0 | 8.4.0-r0 |
| Debian:11 | curl | before 7.74.0-1.3+deb11u10 | 7.74.0-1.3+deb11u10 |
| Debian:12 | curl | before 7.88.1-10+deb12u4 | 7.88.1-10+deb12u4 |
| Debian:13 | curl | before 8.3.0-3 | 8.3.0-3 |
| openSUSE:Leap 15.4 | curl | before 8.0.1-150400.5.32.1 | 8.0.1-150400.5.32.1 |
| openSUSE:Tumbleweed | cmake | before 3.27.8-1.1 | 3.27.8-1.1 |
| openSUSE:Tumbleweed | curl | before 8.4.0-1.1 | 8.4.0-1.1 |
| Red Hat:enterprise_linux:9::appstream | curl-debuginfo | before 0:7.76.1-26.el9_3.2 | 0:7.76.1-26.el9_3.2 |
| Red Hat:enterprise_linux:9::appstream | curl-debuginfo | before 0:7.76.1-23.el9_2.4 | 0:7.76.1-23.el9_2.4 |
| Red Hat:enterprise_linux:9::appstream | curl-debugsource | before 0:7.76.1-26.el9_3.2 | 0:7.76.1-26.el9_3.2 |
| Red Hat:enterprise_linux:9::appstream | curl-debugsource | before 0:7.76.1-23.el9_2.4 | 0:7.76.1-23.el9_2.4 |
| Red Hat:enterprise_linux:9::appstream | curl-minimal-debuginfo | before 0:7.76.1-26.el9_3.2 | 0:7.76.1-26.el9_3.2 |
| Red Hat:enterprise_linux:9::appstream | curl-minimal-debuginfo | before 0:7.76.1-23.el9_2.4 | 0:7.76.1-23.el9_2.4 |
| Red Hat:enterprise_linux:9::appstream | libcurl-debuginfo | before 0:7.76.1-26.el9_3.2 | 0:7.76.1-26.el9_3.2 |
+73
Same product
haxx: all recordsOther highest-scoring records for the same primary product.
- CVE-2019-5436A heap buffer overflow in the TFTP receiving code allows for DoS or arbitrary code execution in libcurl versions 7.19.4 through 7.64.1.46Plan
- CVE-2019-3822libcurl versions from 7.36.0 to before 7.64.0 are vulnerable to a stack-based buffer overflow.43Plan
- CVE-2018-14618curl before version 7.61.1 is vulnerable to a buffer overrun in the NTLM authentication code.42Plan
Published before and after this one in the same product
- ← EarlierCVE-2023-27537Mar 30, 2023 · A double free vulnerability exists in libcurl <8.0.0 when sharing HSTS data between separate "handles".24Monitor
- ← EarlierCVE-2023-27538Mar 30, 2023 · An authentication bypass vulnerability exists in libcurl prior to v8.0.0 where it reuses a previously established SSH connection despite the22Monitor
- Later →CVE-2023-38546Oct 18, 2023 · This flaw allows an attacker to insert cookies at will into a running program
using libcurl, if the specific series of conditions are met.16Monitor
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 |
|---|---|---|
| curl curl | 8.4.0 | Vendor (CNA) |
| almalinux:curl | 7.76.1-23.el9_2.4 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:curl-minimal | 7.76.1-23.el9_2.4 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libcurl | 7.76.1-23.el9_2.4 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libcurl-devel | 7.76.1-23.el9_2.4 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libcurl-minimal | 7.76.1-23.el9_2.4 · AlmaLinux:9 | Package registry (OSV) |
| alpine:curl | 8.4.0-r0 · Alpine:v3.15 | Package registry (OSV) |
| debian:curl | 7.88.1-10+deb12u4 · Debian:12 | Package registry (OSV) |
| opensuse:cmake | 3.27.8-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:curl | 8.0.1-150400.5.32.1 · openSUSE:Leap 15.4 | Package registry (OSV) |
| red hat:curl | 0:7.76.1-14.el9_0.9 · Red Hat:rhel_eus:9.0::baseos | Package registry (OSV) |
| red hat:curl-debuginfo | 0:7.76.1-14.el9_0.9 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:curl-debugsource | 0:7.76.1-14.el9_0.9 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:curl-minimal | 0:7.76.1-14.el9_0.9 · Red Hat:rhel_eus:9.0::baseos | Package registry (OSV) |
| red hat:curl-minimal-debuginfo | 0:7.76.1-14.el9_0.9 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:jbcs-httpd24-openssl | 1:1.1.1k-16.el7jbcs · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jbcs-httpd24-openssl-debuginfo | 1:1.1.1k-16.el7jbcs · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:libcurl | 0:7.76.1-14.el9_0.9 · Red Hat:rhel_eus:9.0::baseos | Package registry (OSV) |
| red hat:libcurl-debuginfo | 0:7.76.1-14.el9_0.9 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:libcurl-devel | 0:7.76.1-14.el9_0.9 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| red hat:libcurl-minimal | 0:7.76.1-14.el9_0.9 · Red Hat:rhel_eus:9.0::baseos | Package registry (OSV) |
| red hat:libcurl-minimal-debuginfo | 0:7.76.1-14.el9_0.9 · Red Hat:rhel_eus:9.0::appstream | Package registry (OSV) |
| rocky linux:curl | 0:7.76.1-23.el9_2.4 · Rocky Linux:9 | Package registry (OSV) |
| suse:curl | 8.0.1-11.74.1 · SUSE:Linux Enterprise Software Development Kit 12 SP5 | Package registry (OSV) |
| suse:curl | 8.0.1-150400.5.32.1 · SUSE:Linux Enterprise Micro 5.3 | Package registry (OSV) |
Exploit status
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Proof-of-concept repository on GitHub ×8
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Proof-of-concept repository on GitHub | stars:20 | 2023-10-11 |
| Proof-of-concept repository on GitHub | stars:8 | 2023-10-12 |
| Proof-of-concept repository on GitHub | stars:6 | 2023-10-12 |
| Proof-of-concept repository on GitHub | stars:3 | 2023-10-12 |
| Proof-of-concept repository on GitHub | stars:2 | 2023-10-16 |
| Proof-of-concept repository on GitHub | stars:4 | 2023-10-16 |
| Proof-of-concept repository on GitHub | stars:21 | 2023-10-17 |
| Proof-of-concept repository on GitHub | stars:0 | 2024-03-19 |
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.
- First PoC-7 d
- Published
- TodayOct 27, 2026+1105 d
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).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-23-0640 · Nov 15, 2023(Fortinet Güvenlik Bildirimi)
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-787 · Out-of-bounds WriteCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- seclists.org/fulldisclosure/2024/Jan/37
- seclists.org/fulldisclosure/2024/Jan/38
- curl.se/docs/CVE-2023-38545.html
- forum.vmssoftware.com/viewtopic.php?f=8&t=8868
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OGMXNRNSJ4ETDK6FRNU3J7SABXPWCHSQ/
- security.netapp.com/advisory/ntap-20231027-0009/
- security.netapp.com/advisory/ntap-20240201-0005/
- support.apple.com/kb/HT214036
- support.apple.com/kb/HT214057
- support.apple.com/kb/HT214058
- support.apple.com/kb/HT214063
- www.secpod.com/blog/high-severity-heap-buffer-overflow-vulnerability/
- cert-portal.siemens.com/productcert/html/ssa-082556.html
- cert-portal.siemens.com/productcert/html/ssa-093430.html
- cert-portal.siemens.com/productcert/html/ssa-507364.html
- cert-portal.siemens.com/productcert/html/ssa-832273.html
- cert-portal.siemens.com/productcert/html/ssa-943925.html
- github.com/UTsweetyfish/CVE-2023-38545
- github.com/bcdannyboy/CVE-2023-38545
Vendor advisories and official records. Exploit/PoC links are deliberately left out.