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CVE-2023-28320· NVD / CVE Program· CNA hackerone

A denial of service vulnerability exists in curl <v8.1.0 in the way libcurl provides several different backends for resolving host names, se

Noroxi assessment

Priority: Monitor (action score 24/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 2.6% (FIRST EPSS); higher than 85.5% 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. Special conditions such as timing or configuration are required.
  • Fixed version: curl (Alpine:v3.15) 8.1.0-r0; curl (Debian:12) 7.88.1-10; curl (openSUSE:Tumbleweed) 8.1.0-1.1.

Low priority for now. Upgrade to curl (Alpine:v3.15) 8.1.0-r0; curl (Debian:12) 7.88.1-10; curl (openSUSE:Tumbleweed) 8.1.0-1.1 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

A denial of service vulnerability exists in curl <v8.1.0 in the way libcurl provides several different backends for resolving host names, selected at build time. If it is built to use the synchronous resolver, it allows name resolves to time-out slow operations using `alarm()` and `siglongjmp()`. When doing this, libcurl used a global buffer that was not mutex protected and a multi-threaded application might therefore crash or otherwise misbehave.

MediumCVSS 5.9 · v3.1—No exploit Fix available
Published
May 26, 2023
Updated
Jun 17, 2026
EPSS
2.6% · 85th percentile

Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.6%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2023-28320

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

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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.

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Affected 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.

VendorProduct
haxxcurl
applemacos
netappclustered data ontap
netappontap antivirus connector
netapph300s firmware
netapph300s
netapph500s firmware
netapph500s
netapph700s firmware
netapph700s
netapph410s firmware
netapph410s

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • apple macos11.0 and later · before 11.7.9
  • apple macos12.0 and later · before 12.6.8
  • apple macos13.0 and later · before 13.5
  • haxx curlbefore 8.1.0
  • netapp clustered data ontapall versions
  • netapp h300s firmwareall versions
  • netapp h410s firmwareall versions
  • netapp h500s firmwareall versions
  • netapp h700s firmwareall versions
  • netapp ontap antivirus connectorall versions

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.

  • n/a https://github.com/curl/curl

    • Fixed in 8.1.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.15curlbefore 8.1.0-r08.1.0-r0
Debian:12curlbefore 7.88.1-107.88.1-10
openSUSE:Tumbleweedcurlbefore 8.1.0-1.18.1.0-1.1
SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSScurlbefore 7.60.0-150000.51.17.60.0-150000.51.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSScurlbefore 7.66.0-150200.4.57.17.66.0-150200.4.57.1
SUSE:Linux Enterprise Micro 5.3curlbefore 8.0.1-150400.5.23.18.0.1-150400.5.23.1
SUSE:Linux Enterprise Micro 5.3curlbefore 8.0.1-150400.5.23.18.0.1-150400.5.23.1
SUSE:Linux Enterprise Server 12 SP2-BCLcurlbefore 7.37.0-37.98.17.37.0-37.98.1
SUSE:Linux Enterprise Software Development Kit 12 SP5curlbefore 8.0.1-11.65.28.0.1-11.65.2
SUSE:OpenStack Cloud 9curlbefore 7.60.0-4.56.17.60.0-4.56.1

Same product

haxx: all records

Other 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 t
    51Plan
  • 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-leak
    45Plan

Published before and after this one in the same product

  • ← EarlierCVE-2023-27534Mar 30, 2023 · A path traversal vulnerability exists in curl <8.0.0 SFTP implementation causes the tilde (~) character to be wrongly replaced when used as
    36Monitor
  • ← EarlierCVE-2023-28319May 26, 2023 · A use after free vulnerability exists in curl <v8.1.0 in the way libcurl offers a feature to verify an SSH server's public key using a SHA 2
    31Monitor
  • Later →CVE-2023-28321May 26, 2023 · An improper certificate validation vulnerability exists in curl <v8.1.0 in the way it supports matching of wildcard patterns when listed as
    24Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
alpine:curl8.1.0-r0 · Alpine:v3.15Package registry (OSV)
debian:curl7.88.1-10 · Debian:12Package registry (OSV)
opensuse:curl8.0.1-150400.5.23.1 · openSUSE:Leap Micro 5.3Package registry (OSV)
suse:curl8.0.1-150400.5.23.1 · SUSE:Linux Enterprise Micro 5.3Package 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.

EPSS, last 120 days

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.

Finders, 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

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

CVSS vector

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

nvd-primary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
function expand(node) {  return node.children.map(expand);}

Fixed

ts
const MAX_DEPTH = 32;function expand(node, depth = 0) {  if (depth > MAX_DEPTH) throw new Error("too deep");  return node.children.map((c) => expand(c, depth + 1));}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

All records