CVE-2021-43396

Exp

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: 2021-11-04 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-43396 is rated High Exploit Risk (75.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 3.06%). 2 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-43396

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-43396

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-07-12 2.94% 3.06% +0.12%
2 2026-06-15 0.60% 2.94% +2.35%
3 2026-01-31 — 0.60% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-43396

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-43396

OS Trackers for CVE-2021-43396

vendor priority summary link
debian unimportant CVE-2021-43396 unimportant priority: Debian including 1 source packages (glibc), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-43396
redhat — — https://access.redhat.com/security/cve/CVE-2021-43396
suse low CVE-2021-43396 severity low: SUSE including 16 source package names (glibc, glibc-32bit, …), 141 product×package rows across 14 product lines (HPE Helion OpenStack 8, SUSE Linux Enterprise Point of Service 11 SP3, … (14 product lines)): Known Not Affected 141. https://www.suse.com/security/cve/CVE-2021-43396/
ubuntu medium CVE-2021-43396 medium priority: Ubuntu including 2 source packages (eglibc, glibc), 16 status rows across 8 suites (bionic, focal, hirsute, impish, jammy, trusty, upstream, xenial): DNE 7, not-affected 7, needs-triage 2. https://ubuntu.com/security/CVE-2021-43396

Affected software / configurations for CVE-2021-43396

Vendor Product Version Raw CPE
gnu glibc 2.34 cpe:2.3:a:gnu:glibc:2.34:*:*:*:*:*:*:*
oracle communications_cloud_native_core_binding_support_function 22.1.3 cpe:2.3:a:oracle:communications_cloud_native_core_binding_support_function:22.1.3:*:*:*:*:*:*:*
oracle communications_cloud_native_core_network_function_cloud_native_environment 22.1.0 cpe:2.3:a:oracle:communications_cloud_native_core_network_function_cloud_native_environment:22.1.0:*:*:*:*:*:*:*
oracle communications_cloud_native_core_network_repository_function 22.1.2 cpe:2.3:a:oracle:communications_cloud_native_core_network_repository_function:22.1.2:*:*:*:*:*:*:*
oracle communications_cloud_native_core_network_repository_function 22.2.0 cpe:2.3:a:oracle:communications_cloud_native_core_network_repository_function:22.2.0:*:*:*:*:*:*:*
oracle communications_cloud_native_core_security_edge_protection_proxy 22.1.1 cpe:2.3:a:oracle:communications_cloud_native_core_security_edge_protection_proxy:22.1.1:*:*:*:*:*:*:*
oracle communications_cloud_native_core_unified_data_repository 22.2.0 cpe:2.3:a:oracle:communications_cloud_native_core_unified_data_repository:22.2.0:*:*:*:*:*:*:*
oracle enterprise_operations_monitor 4.3 cpe:2.3:a:oracle:enterprise_operations_monitor:4.3:*:*:*:*:*:*:*
oracle enterprise_operations_monitor 4.4 cpe:2.3:a:oracle:enterprise_operations_monitor:4.4:*:*:*:*:*:*:*
oracle enterprise_operations_monitor 5.0 cpe:2.3:a:oracle:enterprise_operations_monitor:5.0:*:*:*:*:*:*:*

References for CVE-2021-43396

cvelogic Threat Intelligence