A vulnerability, which was classified as critical, has been found in MicroPython 1.21.0/1.22.0-preview. Affected by this issue is the function poll_set_add_fd of the file extmod/modselect.c. The manipulation leads to use after free. The exploit has been disclosed to the public and may be used. The patch is identified as 8b24aa36ba978eafc6114b6798b47b7bfecdca26. It is recommended to apply a patch to fix this issue. VDB-249158 is the identifier assigned to this vulnerability.
CVE-2023-7152
“—” beside the score: it is equal to NVD's CVSS score.
This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 0.9% (58th percentile of EPSS-scored CVEs). GitHub Security Advisory CVSS 5.5 is lower than this score; a lower GitHub score revises it only when its advisory is newer than the CVE record's last change, and this advisory (published 2023-12-29) is not newer than that change (2026-06-17), so it does not.
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 9.8
- EG Score
- 9.8CRITICALmedium confidence
- EG Risk
- 44EG Risk 44/100
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.Exploitation0.9% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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
- 0.9%
- EPSS %ILE
- 58th
- 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.NVD CVSS v3 · CVSS v3.0 or v3.1
- EG Likelihood
- 0.9% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). 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; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade 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; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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
December 29, 2023
Last Modified
June 17, 2026
Advisory Details (5)
Auto-updated Oct 11, 2026[SECURITY] Fedora 39 Update: micropython-1.22.2-1.fc39 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/[email protected]/message/4E2HYWCZB5R4SHY4SZZZSFDMD64N4SOZ/Use After Free at modselect.c:151 · Issue #12887 · micropython/micropython · GitHub
https://github.com/micropython/micropython/issues/12887commit 8b24aa36ba97 (jimmo/micropython)
Fix landed in jimmo/micropython commit 8b24aa36ba97 — awaiting tagged release
https://github.com/jimmo/micropython/commit/8b24aa36ba978eafc6114b6798b47b7bfecdca26[SECURITY] Fedora 38 Update: micropython-1.22.2-1.fc38 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/[email protected]/message/TEK46QAJOXXDZOWOIE2YACUOCZFWOBCK/[SECURITY] Fedora 40 Update: micropython-1.22.2-1.fc40 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/[email protected]/message/D3WWY5JY4RTJE25APB4REGDUDPATG6H7/Affected Packages
(4 across 1 ecosystem)
PyPI(4)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| micropython-copy | 0.0.1, 0.0.2, 3.3.3-2, 3.3.3.post3 |
| — |
| micropython-io | 0.0.1, 0.0.2, 0.0.3, 0.1 |
| — |
| micropython-os | 0.2.3 ... 0.8 (12 versions) |
| — |
| micropython-select | 0.0.1 ... 0.3 (17 versions) |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× in last 7d / 32× 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 90 of 182 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. 10 repeat rows among the latest 100 are merged into the row they repeat. The 92 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-21 16:29 UTCEPSS rescoreEPSS 0.9% · 58th percentile
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- 2026-10-18 07:37 UTCEG score recompute
- 2026-10-17 16:30 UTCEPSS rescoreEPSS 0.9% · 58th percentile
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- 2026-10-12 16:31 UTCEPSS rescoreEPSS 0.9% · 58th percentile
- 2026-10-12 09:54 UTCOSV refresh
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- 2026-10-11 13:45 UTCEPSS rescoreEPSS 0.9% · 58th percentile
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- 2026-09-30 15:01 UTCEPSS rescoreEPSS 0.9% · 57th percentile
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- 2026-07-23 02:30 UTCEG score recompute
- 2026-07-22 23:17 UTCEG score recompute▲ 4.30
- 2026-07-22 14:07 UTCEPSS rescoreEPSS 0.9% · 55th percentile
Related CVEs(same product + same CWE)
Same product
3 shownPyPI:micropython-os · PyPI:micropython-copy
Frequently asked(5)
What is CVE-2023-7152?
When was the CVE record for CVE-2023-7152 published?
Is CVE-2023-7152 actively exploited?
What is the CVSS score of CVE-2023-7152?
How do I remediate CVE-2023-7152?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2023-7152
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