CVE-2026-48142 | NGINX ngx_http_charset_module vulnerability

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_charset_module module. When content is served or proxied through a location block with both source_charset utf-8; and a charset directive (for example, charset koi8-r;) configured, remote, unauthenticated attackers can send requests (in conjunction with conditions beyond their control) to cause a heap buffer over-read in the NGINX worker process, leading to limited disclosure of memory or a restart. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Published: 2026-06-17 Last update: 2026-06-22 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-48142 is rated Low Risk (35.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.37%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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

Exploit prediction scoring system (EPSS) score for CVE-2026-48142

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 2026-06-18 — 0.37% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-48142

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.3 4.0 MEDIUM
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:H)
Exploitation depends on constrained or hard-to-reproduce conditions.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:L)
Limited confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:N)
No integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:L)
Limited availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.
 — — [email protected]
4.8 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L 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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.2 2.5 [email protected]

Weakness enumeration for CVE-2026-48142

GitHub Security Advisory for CVE-2026-48142

GHSA-2388-jp8v-fg9w · Severity: medium — NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_charset_module module. When...

OS Trackers for CVE-2026-48142

vendor priority summary link
debian not yet assigned CVE-2026-48142 not yet assigned priority: Debian including 1 source packages (nginx), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-48142
suse medium — https://www.suse.com/security/cve/CVE-2026-48142/
ubuntu medium CVE-2026-48142 medium priority: Ubuntu including 1 source packages (nginx), 9 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): needs-triage 5, released 4. https://ubuntu.com/security/CVE-2026-48142

Affected software / configurations for CVE-2026-48142

Vendor Product Version Raw CPE
f5 dos >= 4.3.0, <= 4.7.0 cpe:2.3:a:f5:dos:*:*:*:*:*:nginx:*:*
f5 dos 4.9.0 cpe:2.3:a:f5:dos:4.9.0:*:*:*:*:nginx:*:*
f5 nginx_gateway_fabric >= 1.3.0, <= 1.6.2 cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:*
f5 nginx_gateway_fabric >= 2.0.0, <= 2.6.3 cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:*
f5 nginx_ingress_controller >= 3.5.0, <= 3.7.2 cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:*
f5 nginx_ingress_controller >= 4.0.0, <= 4.0.1 cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:*
f5 nginx_ingress_controller >= 5.0.0, <= 5.5.0 cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:*
f5 nginx_instance_manager >= 2.17.0, <= 2.22.0 cpe:2.3:a:f5:nginx_instance_manager:*:*:*:*:*:*:*:*
f5 nginx_open_source >= 1.0.0, <= 1.30.2 cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*
f5 nginx_open_source >= 1.31.0, <= 1.31.1 cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*
f5 nginx_plus >= 37.0.0, <= 37.0.1 cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:*
f5 nginx_plus >= r33, <= r36 cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:*
f5 waf >= 4.10.0, <= 4.16.0 cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:*
f5 waf >= 5.2.0, <= 5.8.0 cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:*
f5 waf >= 5.9.0, <= 5.13.1 cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:*

References for CVE-2026-48142

cvelogic Threat Intelligence