Calling the scanf family of functions with a %mc (malloc'd character match) in the GNU C Library version 2.7 to version 2.43 with a format width specifier with an explicit width greater than 1024 could result in a one byte heap buffer overflow.
CVE-2026-5450
“—” beside the score: it is equal to the CVSS score beside it.
Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-04-20. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 9.8; sources differ by 0.0.
Also known asEUVD-2026-23978 (ENISA EUVD) · GHSA-v898-xg3c-w4rj (GitHub Security Advisories)Source: ENISA EUVD
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
A fix is available — apply it.
- CVSS v3
- 9.8
- EG Score
- 9.8CRITICALmedium confidence
- EG Risk
- 75EG Risk 75/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity98% × 45%Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.5%
- EPSS %ILE
- 42nd
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-02). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track* at medium mission impactTrack at low, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low, Track* at medium and Attend at high mission impact.
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)3 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
April 20, 2026
Last Modified
October 15, 2026
Advisory Details (3)
Auto-updated Oct 30, 2026The GNU C Library security advisories update for 2026-04-20
https://inbox.sourceware.org/libc-announce/b11f0003-6ec1-4bd6-b9de-9e38a4efeca3@redhat.com/T/#u34008 – (CVE-2026-5450) stdio-common: scanf %mc pattern will cause heap overflow when width > 1024
https://sourceware.org/bugzilla/show_bug.cgi?id=CVE-2026-5450Vendor Advisories for CVE-2026-5450(20)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2026:82888Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.17.2
- RHSA-2026:82857Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
- RHSA-2026:82372Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
- RHSA-2026:82354Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
- RHSA-2026:82347Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
- RHSA-2026:82322Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.17.2
- RHSA-2026:82304Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.17.2
- RHSA-2026:74674Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat AI Base Images 3.4.3 (Neuron)
- +12 more
Patch Availability(30)
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(4 across 4 ecosystems)
Debian:11(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| glibc | 2.31-13 ... 2.43-2 (208 versions) |
| — |
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| glibc | 2.36-10~0 ... 2.44-2 (134 versions) |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| glibc | 2.41-12, 2.41-12+deb13u1, 2.41-12+deb13u2, 2.41-12+deb13u3 |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| glibc | 2.41-12 ... 2.42-9 (24 versions) |
| — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(18)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
- Microsoft MSRCCVE-2026-54502026-04-22
scanf %mc off-by-one heap buffer overflow
- Red HatRHSA-2026:12740MODERATE2026-04-20
RHSA-2026:12740 — Moderate
- Red HatRHSA-2026:33092MODERATE2026-04-20
RHSA-2026:33092 — Moderate
- Red HatRHSA-2026:33126MODERATE2026-04-20
RHSA-2026:33126 — Moderate
- Red HatRHSA-2026:33170MODERATE2026-04-20
RHSA-2026:33170 — Moderate
- Red HatRHSA-2026:33226MODERATE2026-04-20
RHSA-2026:33226 — Moderate
- Red HatRHSA-2026:33227MODERATE2026-04-20
RHSA-2026:33227 — Moderate
- Red HatRHSA-2026:33228MODERATE2026-04-20
RHSA-2026:33228 — Moderate
- Red HatRHSA-2026:33229MODERATE2026-04-20
RHSA-2026:33229 — Moderate
- Red HatRHSA-2026:33230MODERATE2026-04-20
RHSA-2026:33230 — Moderate
- Red HatRHSA-2026:33231MODERATE2026-04-20
RHSA-2026:33231 — Moderate
- Red HatRHSA-2026:34102MODERATE2026-04-20
RHSA-2026:34102 — Moderate
- Red HatRHSA-2026:34211MODERATE2026-04-20
RHSA-2026:34211 — Moderate
- Red HatRHSA-2026:36643MODERATE2026-04-20
RHSA-2026:36643 — Moderate
- Red HatRHSA-2026:37395MODERATE2026-04-20
RHSA-2026:37395 — Moderate
- Red HatRHSA-2026:37396MODERATE2026-04-20
RHSA-2026:37396 — Moderate
- Red HatRHSA-2026:39981MODERATE2026-04-20
RHSA-2026:39981 — Moderate
- Red HatRHSA-2026:40762MODERATE2026-04-20
RHSA-2026:40762 — Moderate
Data Freshness Timeline
(refreshed 28× in last 7d / 105× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 100 of 470 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 370 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-02 20:31 UTCEG score recompute
- 2026-11-02 20:31 UTCVendor advisory
- 2026-11-02 20:31 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-11-01 21:14 UTCEG score recompute
- 2026-11-01 21:14 UTCVendor advisory
- 2026-11-01 21:13 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-10-31 21:58 UTCEG score recompute
- 2026-10-31 21:58 UTCVendor advisory
- 2026-10-31 21:58 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-10-30 22:41 UTCEG score recompute
- 2026-10-30 22:41 UTCVendor advisory
- 2026-10-30 22:41 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-29 23:25 UTCEG score recompute
- 2026-10-29 23:25 UTCVendor advisory
- 2026-10-29 23:25 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-29 00:09 UTCEG score recompute
- 2026-10-29 00:09 UTCVendor advisory
- 2026-10-29 00:09 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-28 00:54 UTCEG score recompute
Show 75 moreShow fewer
- 2026-10-28 00:54 UTCVendor advisory
- 2026-10-28 00:54 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-27 01:35 UTCEG score recompute
- 2026-10-27 01:35 UTCVendor advisory
- 2026-10-27 01:35 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-25 22:23 UTCEG score recompute
- 2026-10-25 22:23 UTCVendor advisory
- 2026-10-25 22:23 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-25 14:19 UTCEG score recompute
- 2026-10-24 23:07 UTCEG score recompute
- 2026-10-24 23:07 UTCVendor advisory
- 2026-10-24 23:07 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-23 23:51 UTCEG score recompute
- 2026-10-23 23:51 UTCVendor advisory
- 2026-10-23 23:51 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-23 00:32 UTCEG score recompute
- 2026-10-23 00:32 UTCVendor advisory
- 2026-10-23 00:32 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-22 01:13 UTCEG score recompute
- 2026-10-22 01:13 UTCVendor advisory
- 2026-10-22 01:13 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-21 01:53 UTCEG score recompute
- 2026-10-21 01:53 UTCVendor advisory
- 2026-10-21 01:53 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-20 02:37 UTCEG score recompute
- 2026-10-20 02:37 UTCVendor advisory
- 2026-10-20 02:37 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-19 02:08 UTCEG score recompute
- 2026-10-19 02:08 UTCVendor advisory
- 2026-10-19 02:08 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-18 03:30 UTCEG score recompute
- 2026-10-18 02:51 UTCEG score recompute
- 2026-10-18 02:51 UTCVendor advisory
- 2026-10-18 02:51 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-17 03:33 UTCEG score recompute
- 2026-10-17 03:33 UTCVendor advisory
- 2026-10-17 03:32 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-16 04:14 UTCEG score recompute
- 2026-10-16 04:14 UTCVendor advisory
- 2026-10-16 04:13 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-15 01:31 UTCEG score recompute
- 2026-10-15 01:31 UTCVendor advisory
- 2026-10-15 01:31 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-14 09:11 UTCEG score recompute
- 2026-10-14 09:11 UTCVendor advisory
- 2026-10-14 09:10 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-13 06:16 UTCEG score recompute
- 2026-10-13 06:16 UTCVendor advisory
- 2026-10-13 06:16 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-12 15:56 UTCEG score recompute
- 2026-10-12 06:56 UTCVendor advisory
- 2026-10-12 06:56 UTCGHSA enrichmentGHSA-v898-xg3c-w4rj · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-11 19:39 UTCEG score recompute
- 2026-10-11 16:54 UTCEG score recompute
- 2026-10-11 14:18 UTCEG score recompute
- 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-11 05:25 UTCOSV refresh
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
Related CVEs(same product + same vendor + same CWE)
Same product
10 shownDebian:11:glibc
- CVE-2015-0235EG 10.0EPSS p100HIGH
- CVE-2008-0122EG 10.0EPSS p96HIGH
- CVE-2025-4802NVD 7.8EG 9.8CRITICAL
- CVE-2022-23219EG 9.8EPSS p92CRITICAL
- CVE-2022-23218EG 9.8EPSS p93CRITICAL
- CVE-2021-33574EG 9.8CRITICAL
- CVE-1999-0199EG 9.8CRITICAL
- CVE-2019-1010022EG 9.8CRITICAL
- CVE-2005-3590EG 9.8CRITICAL
- CVE-2019-9169EG 9.8EPSS p92CRITICAL
Same vendor
10 shownredhat:RHSA-2026:44481 · redhat:RHSA-2026:40762 · redhat:RHSA-2026:34102
Frequently asked(5)
What is CVE-2026-5450?
When was CVE-2026-5450 made public?
Is CVE-2026-5450 actively exploited?
What is the CVSS score of CVE-2026-5450?
How do I remediate CVE-2026-5450?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-5450
Is Your Infrastructure Affected by CVE-2026-5450?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.