High exploit reference

CVE-2021-43396 — In iconvdata/iso-2022-jp-3.c in the GNU C Library (aka glibc) 2.34, remote attackers can force...

In iconvdata/iso-2022-jp-3.c in the GNU C Library (aka glibc) 2.34, remote attackers can force iconv() to emit a spurious '\0' character via crafted ISO-2022-JP-3 data that is accompanied by an internal state reset. This may affect data integrity in certain iconv() use cases. NOTE: the vendor states "the bug cannot be invoked through user input and requires iconv to be invoked with a NULL inbuf, which ought to require a separate application bug to do so unintentionally. Hence there's no security impact to the bug.

Published Nov 4, 2021 · Updated Oct 14, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: mitre

Low

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 3.3% (30-day exploitation probability)+13
Technical severity (high)+6

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

3.29%

ahead of 88% of scored CVEs · Oct 14, 2026

Affects

Gnu

Glibc and 6 more

CVSS base

7.5

High · 2 source(s)

Remediation

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

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.

Identify exposed assets running the affected vendor/product/version combinations (Gnu Glibc, Oracle Communications Cloud Native Core Binding Support Function, Oracle Communications Cloud Native Core Network Function Cloud Native Environment…).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Gnu	Glibc	version 2.34	Vulnerable	NIST National Vulnerability Database
Oracle	Communications Cloud Native Core Binding Support Function	version 22.1.3	Vulnerable	NIST National Vulnerability Database
Oracle	Communications Cloud Native Core Network Function Cloud Native Environment	version 22.1.0	Vulnerable	NIST National Vulnerability Database
Oracle	Communications Cloud Native Core Network Repository Function	version 22.1.2version 22.2.0	Vulnerable	NIST National Vulnerability Database
Oracle	Communications Cloud Native Core Security Edge Protection Proxy	version 22.1.1	Vulnerable	NIST National Vulnerability Database
Oracle	Communications Cloud Native Core Unified Data Repository	version 22.2.0	Vulnerable	NIST National Vulnerability Database
Oracle	Enterprise Operations Monitor	version 4.3version 4.4version 5.0	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

None

Integrity

High

Availability

None

Every base score collected

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

Score	Version	Severity	Expl.	Impact	Scored by
7.5	CVSS 3.1	High	3.9	3.6	nvd@nist.gov via NIST National Vulnerability Database
7.5	CVSS 3.1	High	—	—	GitHub, Inc. via GitHub Security Advisories
5.0	CVSS 2.0	Medium	10.0	2.9	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N (score shown at the top: nvd@nist.gov)

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 3.29%

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
Record published
Oct 14, 2026
Fix documented
Oct 14, 2026 · NIST National Vulnerability Database
Affected products added · gnu/glibc, oracle/communications cloud native core binding support function, oracle/communications cloud native core net
Oct 14, 2026 · NIST National Vulnerability Database
CVSS changed · 7.5
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
2021
CVE published
Nov 4, 2021 · mitre

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

www.oracle.com/security-alerts/cpujul2022.html
Patch, Third Party Advisory, NIST National Vulnerability Database
sourceware.org/bugzilla/show_bug.cgi
Exploit, Issue Tracking, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
github.com/advisories/GHSA-73g2-m4v3-6c2h
GitHub Security Advisories
sourceware.org/git/
GitHub Security Advisories
cert-portal.siemens.com/productcert/html/ssa-398330.html
NIST National Vulnerability Database
nvd.nist.gov/vuln/detail/CVE-2021-43396
GitHub Security Advisories
sourceware.org/git/
x_refsource_MISC, NIST National Vulnerability Database
blog.tuxcare.com/vulnerability/vulnerability-in-iconv-identified-by-tuxcare-team-cve-2
Exploit, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database

Elsewhere on this site

Gnu
every CVE for this vendor

Related CVEs (same products)

Medium CVE-2026-6238 Buffer overread in ns_printrrf with corrupted RDATA field Apr 28, 2026
High CVE-2026-5435 Potential buffer overflow in ns_sprintrrf TSIG handling path Apr 28, 2026
High CVE-2026-5928 Potential buffer under-read in ungetwc Apr 20, 2026
Critical CVE-2026-5450 scanf %mc off-by-one heap buffer overflow Apr 20, 2026
High CVE-2026-4046 iconv crash due to assertion failure with untrusted input Mar 30, 2026
High CVE-2026-4437 gethostbyaddr and gethostbyaddr_r may incorrectly handle DNS response Mar 20, 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 CISA SSVC assessment.
No CWE classification.
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-2021-43396 is "In iconvdata/iso-2022-jp-3.c in the GNU C Library (aka glibc) 2.34, remote attackers can force...", rated High. It affects Glibc (Gnu); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 3.29% 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.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.