CR/LF bytes were not rejected by HTTP client proxy tunnel headers or host.
CVE-2026-1502
“—” beside the score: it is equal to the CVSS score beside it.
This medium-severity CVE scores 5.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6% (46th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Also known asEUVD-2026-21519 (ENISA EUVD) · GHSA-hjxq-7w9q-2jw6 (GitHub Security Advisories)Source: ENISA EUVD
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 5.7
- EG Score
- 5.7MEDIUMmedium confidence
- EG Risk
- 26EG Risk 26/100
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)Severity57% × 45%Impact severity (EG Severity): CVSS 5.7 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.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.Exploitation none (CISA Vulnrichment) · Automatable no (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. - EPSS PROB
- 0.6%
- EPSS %ILE
- 46th
- 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 (5.7): severity, escalated by confirmed exploitation. This CVE's 5.7 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.7 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
- EG Likelihood
- 0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-28). 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 every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade 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 every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (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
April 10, 2026
Last Modified
October 26, 2026
Advisory Details (6)
Auto-updated May 10, 2026oss-security - CPython [CVE-2026-1502] HTTP client proxy tunnel headers not validated for CR/LF
http://www.openwall.com/lists/oss-security/2026/04/11/4Mailman 3 [CVE-2026-1502] HTTP client proxy tunnel headers not validated for CR/LF - Security-announce - python.org
https://mail.python.org/archives/list/security-announce@python.org/thread/2IVPAEQWUJBCTQZEJEVTYCIKSMQPGRZ3/gh-146211: Reject CR/LF in HTTP tunnel request headers by sethmlarson · Pull Request #146212 · python/cpython · GitHub
https://github.com/python/cpython/pull/146212HTTP proxy via "CONNECT" tunneling doesn't sanitize CR/LF · Issue #146211 · python/cpython · GitHub
https://github.com/python/cpython/issues/146211[3.14] gh-146211: Reject CR/LF in HTTP tunnel request headers (GH-146… · python/cpython@b1cf901 · GitHub
https://github.com/python/cpython/commit/b1cf9016335cb637c5a425032e8274a224f4b2edgh-146211: Reject CR/LF in HTTP tunnel request headers (#146212) · python/cpython@05ed7ce · GitHub
https://github.com/python/cpython/commit/05ed7ce7ae9e17c23a04085b2539fe6d6d3cef69Vendor Advisories for CVE-2026-1502(13)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2026:58981Red Hat Product SecurityCritical
Red Hat Security Advisory: Red Hat Update Infrastructure 5.3 Technology Preview security update
- CVE-2026-1502Microsoft Security Response Center (MSRC)Medium
HTTP client proxy tunnel headers not validated for CR/LF
- RHSA-2026:21275Red Hat Product SecurityCritical
Red Hat Security Advisory: Red Hat Update Infrastructure 5.1 security update
- RHSA-2026:19176Red Hat Product SecurityHigh
Red Hat Security Advisory: python3.14 security update
- RHSA-2026:19177Red Hat Product SecurityHigh
Red Hat Security Advisory: python3.12 security update
- RHSA-2026:19064Red Hat Product SecurityHigh
Red Hat Security Advisory: python3.12 security update
- RHSA-2026:19019Red Hat Product SecurityHigh
Red Hat Security Advisory: python3.14 security update
- RHSA-2026:10950Red Hat Product SecurityHigh
Red Hat Security Advisory: python3.12 security update
- +5 more
Patch Availability(12)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| ubuntu | python3.12-venv (3.12.3-1ubuntu0.15) @ noble | 2026-10-29 | ubuntu |
| redhat | rhui5/rhua-tp-rhel9:1787241260 | 2026-08-24 | redhat |
| redhat | rhui5/rhua-rhel9:1779798222 | 2026-05-27 | redhat |
| redhat | python3.14-0:3.14.4-2.el9_8 | 2026-05-19 | redhat |
| redhat | python3.14-0:3.14.4-2.el10_2 | 2026-05-19 | redhat |
| redhat | python3.12-0:3.12.13-2.el9_8 | 2026-05-19 | redhat |
| redhat | python3.12-0:3.12.13-2.el10_2 | 2026-05-19 | redhat |
| redhat | python3.12-0:3.12.13-2.el8_10 | 2026-04-27 | redhat |
| redhat | python3-13-main-3.13.13-1.1.hum1 | 2026-04-23 | redhat |
| redhat | python3-14-main-3.14.4-2.hum1 | 2026-04-21 | redhat |
| redhat | python3-12-main-3.12.13-3.hum1 | 2026-04-17 | redhat |
| redhat | python3-11-main-3.11.15-4.hum1 | 2026-04-17 | redhat |
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
(13 across 7 ecosystems)
Debian:11(3)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| pypy3 | 7.3.10+dfsg-1 ... 7.3.9+dfsg-5 (53 versions) |
| — |
| python2.7 | 2.7.18-10 ... 2.7.18-9 (10 versions) |
| — |
| python3.9 | 3.9.10-1 ... 3.9.9-4 (29 versions) |
| — |
Debian:14(3)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| pypy3 | 7.3.19+dfsg-2 ... 7.3.21+dfsg-4 (9 versions) |
| — |
| python3.13 | 3.13.11-1 ... 3.13.9-1 (7 versions) |
| — |
| python3.14 | 3.14.0-1 ... 3.14.5~rc1-1 (22 versions) |
| — |
Debian:12(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| pypy3 | 7.3.11+dfsg-2 ... 8.0.0+dfsg-1 (31 versions) |
| — |
| python3.11 | 3.11.2-6 ... 3.11.2-6+deb12u8 (9 versions) |
| — |
Debian:13(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| pypy3 | 7.3.19+dfsg-2 ... 8.0.0+dfsg-1 (13 versions) |
| — |
| python3.13 | 3.13.5-2, 3.13.5-2+deb13u1, 3.13.5-2+deb13u2 |
| — |
Alpine:v3.21(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python3 | — |
| — |
Alpine:v3.22(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python3 | — |
| — |
Alpine:v3.23(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python3 | — |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(1)
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.
Data Freshness Timeline
(refreshed 13× in last 7d / 45× 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 261 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 161 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-29 16:03 UTCEG score recompute
- 2026-10-29 16:03 UTCVendor advisory
- 2026-10-29 16:03 UTCGHSA enrichmentGHSA-hjxq-7w9q-2jw6
- 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-26 21:58 UTCEG score recompute
- 2026-10-26 21:58 UTCVendor advisory
- 2026-10-26 21:58 UTCGHSA enrichmentGHSA-hjxq-7w9q-2jw6
- 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-25 14:47 UTCEG score recompute
- 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-23 06:28 UTCEG score recompute
- 2026-10-23 06:28 UTCVendor advisory
- 2026-10-23 06:28 UTCGHSA enrichmentGHSA-hjxq-7w9q-2jw6
- 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.6% · 45th percentile
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- 2026-10-18 05:01 UTCEG score recompute
- 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-12 16:33 UTCEG score recompute
- 2026-10-11 20:10 UTCEG score recompute
- 2026-10-11 17:22 UTCEG score recompute
- 2026-10-11 14:55 UTCEG score recompute
- 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-10 21:03 UTCOSV refresh
- 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-29 15:21 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-27 13:47 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-21 08:19 UTCOSV refresh
- 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-09-16 05:14 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-09-13 16:46 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-09-12 15:00 UTCEPSS rescoreEPSS 0.6% · 45th percentile
- 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-11 09:36 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-02 06:14 UTCOSV refresh
- 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-16 07:01 UTCEG score recompute
- 2026-08-16 07:01 UTCVendor advisory
- 2026-08-16 07:01 UTCGHSA enrichmentGHSA-hjxq-7w9q-2jw6
- 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.6% · 44th percentile
- 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
- 2026-08-14 05:01 UTCEG score recompute
- 2026-08-14 05:01 UTCVendor advisory
- 2026-08-14 05:01 UTCGHSA enrichmentGHSA-hjxq-7w9q-2jw6
- 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
- 2026-08-13 01:23 UTCEG score recompute
- 2026-08-13 01:23 UTCVendor advisory
- 2026-08-13 01:23 UTCGHSA enrichmentGHSA-hjxq-7w9q-2jw6
- 2026-08-13 00:41 UTCEG score recompute
- 2026-08-13 00:41 UTCVendor advisory
- 2026-08-13 00:41 UTCGHSA enrichmentGHSA-hjxq-7w9q-2jw6
- 2026-08-12 19:14 UTCEG score recompute
- 2026-08-12 19:14 UTCVendor advisory
- 2026-08-12 19:14 UTCGHSA enrichmentGHSA-hjxq-7w9q-2jw6
- 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
Related CVEs(same product + same vendor + same CWE)
Same product
10 shownDebian:14:python3.14 · Alpine:v3.21:python3
Same vendor
10 shownredhat:RHSA-2026:10117 · redhat:RHSA-2026:10950 · redhat:RHSA-2026:19019
Frequently asked(5)
What is CVE-2026-1502?
When was the CVE record for CVE-2026-1502 published?
Is CVE-2026-1502 actively exploited?
What is the CVSS score of CVE-2026-1502?
How do I remediate CVE-2026-1502?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-1502
Is Your Infrastructure Affected by CVE-2026-1502?
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