CVE Intelligence
Medium Access control exploit reference

CVE-2021-22897 — curl 7.61.0 through 7.76.1 suffers from exposure of data element to wrong session due to a...

curl 7.61.0 through 7.76.1 suffers from exposure of data element to wrong session due to a mistake in the code for CURLOPT_SSL_CIPHER_LIST when libcurl is built to use the Schannel TLS library. The selected cipher set was stored in a single "static" variable in the library, which has the surprising side-effect that if an application sets up multiple concurrent transfers, the last one that sets the ciphers will accidentally control the set used by all transfers. In a worst-case scenario, this weakens transport security significantly.

Published Jun 11, 2021 · 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 3% (30-day exploitation probability)+13
  • Technical severity (medium)+3
  • CISA SSVC: exploitation "poc"+5
  • 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
2.98%
ahead of 87% of scored CVEs · Oct 14, 2026
Affects
Haxx
Curl and 21 more
CVSS base
5.3
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
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.

  • Documented patch — cert-portal.siemens.com (NIST National Vulnerability Database)
  • Documented patch — curl.se (NIST National Vulnerability Database)
  • Documented patch — github.com (NIST National Vulnerability Database)
  • Documented patch — www.oracle.com (NIST National Vulnerability Database)
  • Documented patch — www.oracle.com (NIST National Vulnerability Database)
  • Documented patch — www.oracle.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 (Haxx Curl, Netapp Cloud Backup, Netapp H300e Firmware…).
  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 (access control), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Haxx Curl ≥ 7.61.0 and ≤ 7.76.1 Vulnerable NIST National Vulnerability Database
Netapp Cloud Backup versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H300e Firmware 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 H500e 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 H700e 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 Hci Compute Node Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp Solidfire & Hci Management Node versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp Solidfire Baseboard Management Controller Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp Solidfire, Enterprise Sds & Hci Storage Node versions not specified by the source Vulnerable NIST National Vulnerability Database
Oracle Communications Cloud Native Core Binding Support Function version 1.11.0 Vulnerable NIST National Vulnerability Database
Oracle Communications Cloud Native Core Network Function Cloud Native Environment version 1.10.0 Vulnerable NIST National Vulnerability Database
Oracle Communications Cloud Native Core Network Repository Function version 1.15.1version 1.15.0 Vulnerable NIST National Vulnerability Database
Oracle Communications Cloud Native Core Network Slice Selection Function version 1.8.0 Vulnerable NIST National Vulnerability Database
Oracle Communications Cloud Native Core Service Communication Proxy version 1.15.0 Vulnerable NIST National Vulnerability Database
Oracle Essbase < 11.1.2.4.047≥ 21.0 and < 21.3 Vulnerable NIST National Vulnerability Database
Oracle Mysql Server ≤ 5.7.34≥ 8.0.0 and ≤ 8.0.25 Vulnerable NIST National Vulnerability Database
Siemens Sinec Infrastructure Network Services < 1.0.1.1 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
None
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
5.3 CVSS 3.1 Medium 3.9 1.4 nvd@nist.gov via NIST National Vulnerability Database
5.3 CVSS 3.1 Medium 3.9 1.4 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database
5.3 CVSS 3.1 Medium — — GitHub, Inc. via GitHub Security Advisories
5.3 CVSS 3.1 Medium — — CISA-ADP via CVE Program (cve.org) e CISA ADP
4.3 CVSS 2.0 Medium 8.6 2.9 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-668 · Exposure of Resource to Wrong Sphere

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 2.98%

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).
  • Audit administrative actions and access to resources outside each user’s normal pattern.
web/proxy/WAF logsnetwork IDS/IPSauthentication logsapplication logs

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
  • Fix documented
    Oct 14, 2026 · NIST National Vulnerability Database
  • Affected products added · haxx/curl, oracle/communications cloud native core binding support function, oracle/communications cloud native core net
    Oct 14, 2026 · NIST National Vulnerability Database
  • CVSS changed · 5.3
    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
  • 2021
  • CVE published
    Jun 11, 2021 · 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

13 on the record

Elsewhere on this site

Haxx
every CVE for this vendor
Access control
same class
CWE-668
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-80231 A flaw in libcurl makes it wrongly reuse an existing HTTPS connection setup for a given… Sep 6, 2026
  • CVE-2026-80229 Use After Free in Haxx Curl Sep 6, 2026
  • CVE-2026-80230 Improper Certificate Validation in Haxx Curl Sep 6, 2026
  • CVE-2026-82208 Improper Certificate Validation in Haxx Curl Sep 6, 2026
  • CVE-2026-82209 Insertion of Sensitive Information Into Sent Data in Haxx Curl Sep 6, 2026
  • CVE-2026-80255 Insertion of Sensitive Information Into Sent Data in Haxx Curl Sep 6, 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 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-2021-22897 is "curl 7.61.0 through 7.76.1 suffers from exposure of data element to wrong session due to a...", 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 5.3 describes technical severity. EPSS 2.98% 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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