Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU.
CVE-2026-42504
“—” beside the score: it is equal to the CVSS score beside it.
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-06-03. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.5; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5HIGHmedium confidence
- EG Risk
- 49EG Risk 49/100
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)Severity75% × 45%Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.6% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (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
- 0.6%
- EPSS %ILE
- 45th
- 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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-21). 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 or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (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)14 days if the affected system is publicly exposed; 60 days if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (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
June 2, 2026
Last Modified
October 21, 2026
Advisory Details (4)
Auto-updated Jun 11, 2026mime: quadratic complexity in WordDecoder.DecodeHeader · Issue #79217 · golang/go · GitHub
https://go.dev/issue/79217Vendor Advisories for CVE-2026-42504(20)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2026:87246Red Hat Product SecurityHigh
Red Hat Security Advisory: go-toolset:rhel8 security, bug fix, and enhancement update
- RHSA-2026:83631Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat build of MicroShift 4.16.73 security update
- RHSA-2026:77319Red Hat Product SecurityHigh
Red Hat Security Advisory: OpenShift Container Platform 4.13.72 packages and security update
- RHSA-2026:80167Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat build of MicroShift 4.18.57 security update
- 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-2026:80684Red Hat Product SecurityHigh
Red Hat Security Advisory: Updated Red Hat OpenStack Platform 17.1 director Operator container images
- +12 more
Patch Availability(27)
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
(6 across 5 ecosystems)
Debian:14(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| golang-1.25 | 1.25.0-1 ... 1.25.9-1 (15 versions) |
| — |
| golang-1.26 | 1.26.0-1 ... 1.26~rc3-2 (13 versions) |
| — |
Debian:11(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| golang-1.15 | 1.15.15-1 ... 1.15.9-6 (10 versions) |
| — |
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| golang-1.19 | 1.19.10-1 ... 1.19.9-1 (12 versions) |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| golang-1.24 | 1.24.12-1 ... 1.24.9-1 (10 versions) |
| — |
Go(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| stdlib | — |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(25)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
- Microsoft MSRCCVE-2026-425042026-06-05
Quadratic complexity in WordDecoder.DecodeHeader in mime
- Red HatRHSA-2026:23262IMPORTANT2026-06-02
RHSA-2026:23262 — Important
- Red HatRHSA-2026:23264IMPORTANT2026-06-02
RHSA-2026:23264 — Important
- Red HatRHSA-2026:29980IMPORTANT2026-06-02
RHSA-2026:29980 — Important
- Red HatRHSA-2026:29981IMPORTANT2026-06-02
RHSA-2026:29981 — Important
- Red HatRHSA-2026:38995IMPORTANT2026-06-02
RHSA-2026:38995 — Important
- Red HatRHSA-2026:41066IMPORTANT2026-06-02
RHSA-2026:41066 — Important
- Red HatRHSA-2026:41929IMPORTANT2026-06-02
RHSA-2026:41929 — Important
- Red HatRHSA-2026:42043IMPORTANT2026-06-02
RHSA-2026:42043 — Important
- Red HatRHSA-2026:42047IMPORTANT2026-06-02
RHSA-2026:42047 — Important
- Red HatRHSA-2026:42048IMPORTANT2026-06-02
RHSA-2026:42048 — Important
- Red HatRHSA-2026:42049IMPORTANT2026-06-02
RHSA-2026:42049 — Important
- Red HatRHSA-2026:42050IMPORTANT2026-06-02
RHSA-2026:42050 — Important
- Red HatRHSA-2026:42051IMPORTANT2026-06-02
RHSA-2026:42051 — Important
- Red HatRHSA-2026:42644IMPORTANT2026-06-02
RHSA-2026:42644 — Important
- Red HatRHSA-2026:43038IMPORTANT2026-06-02
RHSA-2026:43038 — Important
- Red HatRHSA-2026:47952IMPORTANT2026-06-02
RHSA-2026:47952 — Important
- Red HatRHSA-2026:48151IMPORTANT2026-06-02
RHSA-2026:48151 — Important
- Red HatRHSA-2026:48891IMPORTANT2026-06-02
RHSA-2026:48891 — Important
- Red HatRHSA-2026:49642IMPORTANT2026-06-02
RHSA-2026:49642 — Important
- Red HatRHSA-2026:49712IMPORTANT2026-06-02
RHSA-2026:49712 — Important
- Red HatRHSA-2026:50205IMPORTANT2026-06-02
RHSA-2026:50205 — Important
- Red HatRHSA-2026:50300IMPORTANT2026-06-02
RHSA-2026:50300 — Important
- Red HatRHSA-2026:50319IMPORTANT2026-06-02
RHSA-2026:50319 — Important
- Red HatRHSA-2026:50336IMPORTANT2026-06-02
RHSA-2026:50336 — Important
Data Freshness Timeline
(refreshed 75× in last 7d / 158× 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 563 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 463 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-21 22:32 UTCVendor advisory
- 2026-10-21 22:31 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-21 16:43 UTCEG score recompute
- 2026-10-21 16:43 UTCVendor advisory
- 2026-10-21 16:43 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-21 10:34 UTCVendor advisory
- 2026-10-21 10:33 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-21 04:32 UTCVendor advisory
- 2026-10-21 04:32 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-21 01:18 UTCVendor advisory
- 2026-10-21 01:18 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-20 22:37 UTCVendor advisory
- 2026-10-20 22:37 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-20 16:37 UTCEG score recompute
- 2026-10-20 16:37 UTCVendor advisory
- 2026-10-20 16:37 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-20 10:36 UTCVendor advisory
- 2026-10-20 10:35 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-20 04:39 UTCVendor advisory
- 2026-10-20 04:39 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-20 01:11 UTCVendor advisory
- 2026-10-20 01:11 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-19 22:40 UTCVendor advisory
Show 75 moreShow fewer
- 2026-10-19 22:40 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-19 16:34 UTCEG score recompute
- 2026-10-19 16:34 UTCVendor advisory
- 2026-10-19 16:33 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-19 10:39 UTCVendor advisory
- 2026-10-19 10:39 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-19 04:31 UTCVendor advisory
- 2026-10-19 04:30 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-18 22:33 UTCVendor advisory
- 2026-10-18 22:33 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-18 16:36 UTCEG score recompute
- 2026-10-18 16:36 UTCVendor advisory
- 2026-10-18 16:35 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-18 10:35 UTCVendor advisory
- 2026-10-18 10:35 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-18 04:31 UTCVendor advisory
- 2026-10-18 04:31 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-18 03:41 UTCEG score recompute
- 2026-10-17 22:29 UTCVendor advisory
- 2026-10-17 22:28 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-17 16:39 UTCEG score recompute
- 2026-10-17 16:39 UTCVendor advisory
- 2026-10-17 16:39 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-17 10:35 UTCVendor advisory
- 2026-10-17 10:35 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-17 04:38 UTCVendor advisory
- 2026-10-17 04:38 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-16 22:34 UTCVendor advisory
- 2026-10-16 22:34 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-16 16:48 UTCEG score recompute
- 2026-10-16 16:48 UTCVendor advisory
- 2026-10-16 16:48 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-16 10:38 UTCVendor advisory
- 2026-10-16 10:38 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-16 04:30 UTCVendor advisory
- 2026-10-16 04:29 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-15 22:40 UTCVendor advisory
- 2026-10-15 22:39 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-15 16:39 UTCEG score recompute
- 2026-10-15 16:39 UTCVendor advisory
- 2026-10-15 16:39 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-15 10:42 UTCVendor advisory
- 2026-10-15 10:42 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-15 04:31 UTCVendor advisory
- 2026-10-15 04:30 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-14 22:34 UTCEG score recompute
- 2026-10-14 22:34 UTCVendor advisory
- 2026-10-14 22:34 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-14 10:40 UTCVendor advisory
- 2026-10-14 10:40 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-14 04:46 UTCVendor advisory
- 2026-10-14 04:46 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-13 22:32 UTCVendor advisory
- 2026-10-13 22:31 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-13 16:40 UTCEG score recompute
- 2026-10-13 16:40 UTCVendor advisory
- 2026-10-13 16:39 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-13 10:41 UTCVendor advisory
- 2026-10-13 10:41 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-13 04:45 UTCVendor advisory
- 2026-10-13 04:45 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-12 22:43 UTCVendor advisory
- 2026-10-12 22:43 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-12 16:41 UTCEG score recompute
- 2026-10-12 16:41 UTCVendor advisory
- 2026-10-12 16:40 UTCGHSA enrichmentGHSA-h524-452v-82p9 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-12 16:07 UTCEG score recompute
Related CVEs(same product + same vendor + same CWE)
Same product
10 shownDebian:14:golang-1.26
Same vendor
10 shownredhat:RHSA-2026:23262 · redhat:RHSA-2026:41066 · redhat:RHSA-2026:42043
Frequently asked(5)
What is CVE-2026-42504?
When was the CVE record for CVE-2026-42504 published?
Is CVE-2026-42504 actively exploited?
What is the CVSS score of CVE-2026-42504?
How do I remediate CVE-2026-42504?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-42504
Is Your Infrastructure Affected by CVE-2026-42504?
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