CVE Intelligence
Medium Logic error exploit reference

CVE-2023-28320 — A denial of service vulnerability exists in curl <v8.1.0 in the way libcurl provides several...

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.

Published May 26, 2023 · Updated Oct 23, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: hackerone

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 2.7% (30-day exploitation probability)+13
  • Technical severity (medium)+3
  • CISA SSVC: exploitation "poc"+5

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

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

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
2.66%
ahead of 86% of scored CVEs · Oct 28, 2026
Affects
Apple
Macos and 7 more
CVSS base
5.9
Medium · 4 source(s)

CISA SSVC assessment CISA

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

Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — hackerone.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Apple Macos, Haxx Curl, Netapp Clustered Data Ontap…).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. Apply the fixed version or the patch documented under Remediation.
  4. Search available logs for exploit probes matching the vulnerability class (logic error), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Apple Macos ≥ 11.0 and < 11.7.9≥ 12.0 and < 12.6.8≥ 13.0 and < 13.5 Vulnerable NIST National Vulnerability Database
Haxx Curl < 8.1.0 Vulnerable NIST National Vulnerability Database
Netapp Clustered Data Ontap versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H300s Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H410s Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H500s Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H700s Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp Ontap Antivirus Connector versions not specified by the source Vulnerable NIST National Vulnerability Database

Attack characteristics

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

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

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

ScoreVersionSeverityExpl.ImpactScored by
5.9 CVSS 3.1 Medium 2.2 3.6 nvd@nist.gov via NIST National Vulnerability Database
5.9 CVSS 3.1 Medium 2.2 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database
5.9 CVSS 3.1 Medium — — GitHub, Inc. via GitHub Security Advisories
5.9 CVSS 3.1 Medium — — CISA-ADP via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-362 · Race Condition

Other CVEs with this weakness →

EPSS over time FIRST

Oct 23, 2026 → Oct 28, 2026 · 6 reading(s) · max 2.66%

Detection

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

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • SSVC assessment updated
    Oct 23, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 23, 2026
  • Fix documented
    Oct 23, 2026 · NIST National Vulnerability Database
  • Affected products added · haxx/curl, apple/macos, netapp/clustered data ontap, netapp/ontap antivirus connector, netapp/h300s firmware, netapp/h50
    Oct 23, 2026 · NIST National Vulnerability Database
  • CVSS changed · 5.9
    Oct 23, 2026 · NIST National Vulnerability Database
  • Source status changed · → Modified
    Oct 23, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 23, 2026 · Alertas do Telegram
  • 2023
  • CVE published
    May 26, 2023 · hackerone

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 23, 2026 – Oct 23, 2026
  • 1× Official description updated · Oct 23, 2026 – Oct 23, 2026

References

12 on the record

Elsewhere on this site

Apple
every CVE for this vendor
Logic error
same class
CWE-362
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-86992 The issue was addressed with improved memory handling. This issue is fixed in iOS 26.7.2 and... 2d
  • CVE-2026-86991 A buffer overflow was addressed with improved bounds checking. This issue is fixed in iOS 26.7.2... 2d
  • CVE-2026-86986 A use-after-free issue was addressed with improved memory management. This issue is… 2d
  • CVE-2026-86985 This issue was addressed with improved input validation. This issue is fixed in Safari 27.2, iOS... 2d
  • CVE-2026-86988 The issue was addressed with improved checks. This issue is fixed in iOS 27.2 and iPadOS 27.2,... 2d
  • CVE-2026-86990 An access issue was addressed with improved access restrictions. This issue is fixed in iOS 18.7... 2d

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.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware 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 record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2023-28320 is "A denial of service vulnerability exists in curl <v8.1.0 in the way libcurl provides several...", rated Medium. It affects Macos (Apple); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.9 describes technical severity. EPSS 2.66% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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