There is an issue in CPython when using bytes.decode("unicode_escape", error="ignore|replace"). If you are not using the "unicode_escape" encoding or an error handler your usage is not affected. To work-around this issue you may stop using the error= handler and instead wrap the bytes.decode() call in a try-except catching the DecodeError.
CVE-2025-4516
“—” beside the score: it is equal to NVD's CVSS score.
This medium-severity CVE scores 5.9 under NVD CVSS v3. EPSS exploit probability: 0.2% (13th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Also known asEUVD-2025-15156 (ENISA EUVD) · GHSA-j8r3-cghj-9jhg (GitHub Security Advisories)Source: ENISA EUVD
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 5.9
- EG Score
- 5.9MEDIUMmedium confidence
- EG Risk
- 27EG Risk 27/100
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)Severity59% × 45%Impact severity (EG Severity): CVSS 5.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.2% × 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
- 0.2%
- EPSS %ILE
- 13th
- 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 (5.9): severity, escalated by confirmed exploitation. This CVE's 5.9 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.9 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). 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
May 15, 2025
Last Modified
July 31, 2026
Advisory Details (10)
Auto-updated Jul 30, 2026commit ab9893c40609 (python/cpython)
Fix landed in python/cpython commit ab9893c40609 — awaiting tagged release
https://github.com/python/cpython/commit/ab9893c40609935e0d40a6d2a7307ea51aec598bcommit 8d35fd1b3493 (python/cpython)
Fix landed in python/cpython commit 8d35fd1b3493 — awaiting tagged release
https://github.com/python/cpython/commit/8d35fd1b34935221aff23a1ab69a429dd156be77commit 73b3040f5924 (python/cpython)
Fix landed in python/cpython commit 73b3040f5924 — awaiting tagged release
https://github.com/python/cpython/commit/73b3040f592436385007918887b7e2132aa8431fcommit 6279eb8c076d (python/cpython)
Fix landed in python/cpython commit 6279eb8c076d — awaiting tagged release
https://github.com/python/cpython/commit/6279eb8c076d89d3739a6edb393e43c7929b429dcommit 4398b788ffc1 (python/cpython)
Fix landed in python/cpython commit 4398b788ffc1 — awaiting tagged release
https://github.com/python/cpython/commit/4398b788ffc1f954a2c552da285477d42a571292commit 9f69a58623bd (python/cpython)
Fix landed in python/cpython commit 9f69a58623bd — awaiting tagged release
https://github.com/python/cpython/commit/9f69a58623bd01349a18ba0c7a9cb1dad6a51e8ecommit 69b4387f78f4 (python/cpython)
Fix landed in python/cpython commit 69b4387f78f4 — awaiting tagged release
https://github.com/python/cpython/commit/69b4387f78f413e8c47572a85b3478c47eba8142Mailman 3 [CVE-2025-4516] Use-after-free crash using bytes.decode("unicode_escape", error="ignore|replace") - Security-announce - python.org
https://mail.python.org/archives/list/security-announce@python.org/thread/L75IPBBTSCYEF56I2M4KIW353BB3AY74/gh-133767: Fix use-after-free in the unicode-escape decoder with an error handler
Fix merged in python/cpython PR #129648 on 2025-05-12 — awaiting tagged release
https://github.com/python/cpython/pull/129648Use-after-free in `unicode_escape` decoder with error handler · Issue #133767 · python/cpython · GitHub
https://github.com/python/cpython/issues/133767Vendor Advisories for CVE-2025-4516(2)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(2)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| ubuntu | python3.12-venv (3.12.7-1ubuntu2.1) @ oracular | 2026-10-23 | ubuntu |
| redhat | python39-devel:3.9-8100020251126112422.d47b87a4 | 2025-12-18 | 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
(11 across 11 ecosystems)
Alpine:v3.18(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python3 | — |
| — |
Alpine:v3.19(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python3 | — |
| — |
Alpine:v3.20(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python3 | — |
| — |
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 | — |
| — |
Alpine:v3.24(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python3 | — |
| — |
Debian:11(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python3.9 | 3.9.2-1, 3.9.2-1+deb11u1, 3.9.2-1+deb11u2, 3.9.2-1+deb11u3 |
| — |
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python3.11 | 3.11.2-6 ... 3.11.2-6+deb12u6 (7 versions) |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python3.13 | — |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python3.13 | — |
| — |
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 7× in last 7d / 40× 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 95 of 251 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. 5 repeat rows among the latest 100 are merged into the row they repeat. The 156 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-31 16:31 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-30 16:32 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-29 16:31 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-28 16:30 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-27 16:30 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-25 16:31 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-25 16:24 UTCEG score recompute
- 2026-10-24 16:31 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-23 18:53 UTCEG score recompute
- 2026-10-23 18:53 UTCVendor advisory
- 2026-10-23 18:53 UTCGHSA enrichmentGHSA-j8r3-cghj-9jhg
- 2026-10-23 16:30 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-22 16:33 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-21 16:31 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-20 16:31 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-18 05:32 UTCEG score recompute
- 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-16 16:38 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-14 16:31 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-13 16:32 UTCEPSS rescoreEPSS 0.2% · 12th percentile
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- 2026-10-12 17:03 UTCEG score recompute
- 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-11 20:36 UTCEG score recompute
- 2026-10-11 18:48 UTCEG score recompute
- 2026-10-11 15:24 UTCEG score recompute
- 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-10-10 10:03 UTCOSV refresh
- 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-10-08 17:10 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.2% · 10th percentile
- 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.2% · 10th percentile
- 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.2% · 10th percentile
- 2026-10-03 14:24 UTCEPSS rescoreEPSS 0.2% · 10th percentile
- 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.2% · 10th percentile
- 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.2% · 10th percentile
- 2026-09-28 13:50 UTCEPSS rescoreEPSS 0.2% · 10th percentile
- 2026-09-27 13:45 UTCEPSS rescoreEPSS 0.2% · 10th percentile
- 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.2% · 10th percentile
- 2026-09-26 00:25 UTCEPSS rescoreEPSS 0.2% · 10th percentile
- 2026-09-24 14:02 UTCEPSS rescoreEPSS 0.2% · 10th percentile
- 2026-09-23 13:47 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-09-21 21:06 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-09-20 19:44 UTCOSV refresh
- 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-09-17 19:29 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-09-15 03:09 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-09-12 15:00 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-09-11 09:36 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-09-08 21:59 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-09-07 16:00 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-09-06 13:46 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-09-05 15:28 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-09-01 19:35 UTCOSV refresh
- 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-09-01 04:38 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-08-30 19:16 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-08-30 01:21 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-08-28 21:40 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-08-27 14:24 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-08-26 14:45 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-08-24 14:16 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-08-24 09:22 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-08-23 00:18 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-08-21 23:48 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-08-20 22:54 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-08-18 13:47 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-08-17 13:46 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-08-16 14:55 UTCEPSS rescoreEPSS 0.2% · 12th percentile
- 2026-08-16 02:13 UTCEPSS rescoreEPSS 0.2% · 10th percentile
- 2026-08-15 21:07 UTCOSV refresh
- 2026-08-15 01:29 UTCEPSS rescoreEPSS 0.2% · 9th percentile
- 2026-08-13 21:59 UTCEPSS rescoreEPSS 0.2% · 9th percentile
- 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.2% · 9th percentile
- 2026-08-11 13:41 UTCEPSS rescoreEPSS 0.2% · 9th percentile
- 2026-08-10 23:59 UTCEPSS rescoreEPSS 0.2% · 9th percentile
- 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.2% · 9th percentile
- 2026-08-08 16:36 UTCEPSS rescoreEPSS 0.2% · 9th percentile
- 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.2% · 9th percentile
- 2026-08-05 19:16 UTCEPSS rescoreEPSS 0.2% · 9th percentile
- 2026-08-04 15:09 UTCEPSS rescoreEPSS 0.2% · 8th percentile
Related CVEs(same product + same vendor + same CWE)
Same product
10 shownAlpine:v3.18:python3
Same vendor
10 shownredhat:RHSA-2025:23530
Frequently asked(5)
What is CVE-2025-4516?
When was the CVE record for CVE-2025-4516 published?
Is CVE-2025-4516 actively exploited?
What is the CVSS score of CVE-2025-4516?
How do I remediate CVE-2025-4516?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2025-4516
Is Your Infrastructure Affected by CVE-2025-4516?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.