CVE Intelligence
Medium Cryptography

CVE-2023-23915 — A cleartext transmission of sensitive information vulnerability exists in curl <v7.88.0 that...

A cleartext transmission of sensitive information vulnerability exists in curl <v7.88.0 that could cause HSTS functionality to behave incorrectly when multiple URLs are requested in parallel. Using its HSTS support, curl can be instructed to use HTTPS instead of using an insecure clear-text HTTP step even when HTTP is provided in the URL. This HSTS mechanism would however surprisingly fail when multiple transfers are done in parallel as the HSTS cache file gets overwritten by the most recentlycompleted transfer. A later HTTP-only transfer to the earlier host name would then *not* get upgraded properly to HSTS.

Published Feb 23, 2023 · Updated Oct 14, 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 0.9% (30-day exploitation probability)+9
  • Technical severity (medium)+3
  • Automatable exploitation (SSVC)+3

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
0.86%
ahead of 58% of scored CVEs · Oct 14, 2026
Affects
Haxx
Curl and 7 more
CVSS base
6.5
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
None
none · proof-of-concept · active
Automatable
Yes
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.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

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 (Haxx Curl, Netapp Active Iq Unified Manager, Netapp Clustered Data Ontap…).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes matching the vulnerability class (cryptography), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Haxx Curl ≥ 7.77.0 and < 7.88.0 Vulnerable NIST National Vulnerability Database
Netapp Active Iq Unified Manager versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp Clustered Data Ontap version 9.0 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
Splunk Universal Forwarder ≥ 8.2.0 and < 8.2.12≥ 9.0.0 and < 9.0.6version 9.1.0 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
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

Every base score collected

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

ScoreVersionSeverityExpl.ImpactScored by
6.5 CVSS 3.1 Medium 3.9 2.5 nvd@nist.gov via NIST National Vulnerability Database
6.5 CVSS 3.1 Medium 3.9 2.5 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database
6.5 CVSS 3.1 Medium — — GitHub, Inc. via GitHub Security Advisories
6.5 CVSS 3.1 Medium — — CISA-ADP via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-319 · Cleartext Transmission of Sensitive Information

Other CVEs with this weakness →

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).
  • Check TLS negotiations and unexpected certificates in the component’s traffic.
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • SSVC assessment updated
    Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 14, 2026
  • Affected products added · haxx/curl, netapp/active iq unified manager, netapp/clustered data ontap, netapp/h300s firmware, netapp/h500s firmware,
    Oct 14, 2026 · NIST National Vulnerability Database
  • CVSS changed · 6.5
    Oct 14, 2026 · NIST National Vulnerability Database
  • Source status changed · → Modified
    Oct 14, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 14, 2026 · Alertas do Telegram
  • 2023
  • CVE published
    Feb 23, 2023 · hackerone

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 14, 2026 – Oct 14, 2026
  • 1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

8 on the record

Elsewhere on this site

Haxx
every CVE for this vendor
Cryptography
same class
CWE-319
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-7168 cross-proxy Digest auth state leak May 13, 2026
  • CVE-2026-7009 OCSP stapling bypass with Apple SecTrust May 13, 2026
  • CVE-2026-5545 wrong reuse of HTTP Negotiate connection May 13, 2026
  • CVE-2026-5773 wrong reuse of SMB connection May 13, 2026
  • CVE-2026-6253 proxy credentials leak over redirect-to proxy May 13, 2026
  • CVE-2026-6429 netrc credential leak with reused proxy connection May 13, 2026

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 fixed version, patch or mitigation documented.
  • 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-2023-23915 is "A cleartext transmission of sensitive information vulnerability exists in curl <v7.88.0 that...", rated Medium. It affects Curl (Haxx); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. EPSS 0.86% 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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