CVE-2023-33975

CRITICALNVD 9.89.8
EchelonGraph scoreMEDIUM confidence

“—” 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: 1.5% (73rd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
Elevated

Also known asEUVD-2023-38101 (ENISA EUVD)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan mitigationNo release containing the referenced fix is confirmed: check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 1.5%CVSS: 9.8Exploit: No code on recordExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

RIOT-OS, an operating system for Internet of Things (IoT) devices, contains a network stack with the ability to process 6LoWPAN frames. In version 2023.01 and prior, an attacker can send a crafted frame to the device resulting in an out of bounds write in the packet buffer. The overflow can be used to corrupt other packets and the allocator metadata. Corrupting a pointer will easily lead to denial of service. While carefully manipulating the allocator metadata gives an attacker the possibility to write data to arbitrary locations and thus execute arbitrary code. This issue is fixed in pull request 19680. As a workaround, disable support for fragmented IP datagrams.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
75
EG 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 referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.
EPSS PROB
1.5%
EPSS %ILE
73rd
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
1.5% 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.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.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 referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule 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.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.

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

May 30, 2023

Last Modified

November 21, 2024

Advisory Details (8)

Auto-updated Oct 10, 2026
Fix referenced — no release confirmed yet. Sources: github_commit, github_pr, github.
Web page

RIOT/sys/net/gnrc/network_layer/sixlowpan/frag/rb/gnrc_sixlowpan_frag_rb.c at f41b4b67b6affca0a8b32edced7f51088696869a · RIOT-OS/RIOT · GitHub

https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/frag/rb/gnrc_sixlowpan_frag_rb.c#L388
Web page

RIOT/sys/net/gnrc/network_layer/sixlowpan/frag/rb/gnrc_sixlowpan_frag_rb.c at f41b4b67b6affca0a8b32edced7f51088696869a · RIOT-OS/RIOT · GitHub

https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/frag/rb/gnrc_sixlowpan_frag_rb.c#L320
GitHub advisoryMentions a patch (unverified)

Out of Bounds Write in _rbuf_add · Advisory · RIOT-OS/RIOT · GitHub

https://github.com/RIOT-OS/RIOT/security/advisories/GHSA-f6ff-g7mh-58q4
GitHub pull request

gnrc_sixlowpan_frag_rb: fix OOB write in _rbuf_add

Fix merged in RIOT-OS/RIOT PR #19680 on 2023-05-30 — awaiting tagged release

https://github.com/RIOT-OS/RIOT/pull/19680
GitHub commit

commit 1aeb90ee5555 (RIOT-OS/RIOT)

Fix landed in RIOT-OS/RIOT commit 1aeb90ee5555 — awaiting tagged release

https://github.com/RIOT-OS/RIOT/commit/1aeb90ee5555ae78b567a6365ae4ab71bfd1404b
Web page

RIOT/sys/net/gnrc/network_layer/sixlowpan/frag/rb/gnrc_sixlowpan_frag_rb.c at f41b4b67b6affca0a8b32edced7f51088696869a · RIOT-OS/RIOT · GitHub

https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/frag/rb/gnrc_sixlowpan_frag_rb.c#L480
Web page

RIOT/sys/net/gnrc/network_layer/sixlowpan/frag/rb/gnrc_sixlowpan_frag_rb.c at f41b4b67b6affca0a8b32edced7f51088696869a · RIOT-OS/RIOT · GitHub

https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/frag/rb/gnrc_sixlowpan_frag_rb.c#L467
Web page

RIOT/sys/net/gnrc/network_layer/sixlowpan/frag/rb/gnrc_sixlowpan_frag_rb.c at f41b4b67b6affca0a8b32edced7f51088696869a · RIOT-OS/RIOT · GitHub

https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/frag/rb/gnrc_sixlowpan_frag_rb.c#L463

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 50× 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 99 of 232 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. 1 repeat row among the latest 100 is merged into the row it repeats. The 133 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 17:19 UTCEG score recompute
  2. 2026-11-02 16:39 UTCEPSS rescoreEPSS 1.5% · 73rd percentile
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  1. 2026-10-20 16:29 UTCEPSS rescoreEPSS 1.5% · 73rd percentile
  2. 2026-10-20 06:01 UTCEG score recompute
  3. 2026-10-19 16:29 UTCEPSS rescoreEPSS 1.5% · 73rd percentile
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  5. 2026-10-18 16:29 UTCEPSS rescoreEPSS 1.5% · 73rd percentile
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  9. 2026-10-16 16:35 UTCEPSS rescoreEPSS 1.5% · 73rd percentile
  10. 2026-10-16 02:22 UTCEG score recompute
  11. 2026-10-15 16:29 UTCEPSS rescoreEPSS 1.5% · 73rd percentile
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  14. 2026-10-13 17:57 UTCEG score recompute
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  17. 2026-10-12 16:30 UTCEPSS rescoreEPSS 1.5% · 73rd percentile
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  19. 2026-10-11 13:45 UTCEPSS rescoreEPSS 1.5% · 73rd percentile
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  27. 2026-09-30 16:24 UTCEG score recompute
  28. 2026-09-30 15:01 UTCEPSS rescoreEPSS 1.5% · 72nd percentile
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  36. 2026-09-23 10:53 UTCOSV refresh
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  49. 2026-09-04 05:46 UTCOSV refresh
  50. 2026-09-04 05:04 UTCEPSS rescoreEPSS 1.5% · 72nd percentile
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  65. 2026-08-17 16:29 UTCOSV refresh
  66. 2026-08-17 13:45 UTCEPSS rescoreEPSS 1.5% · 71st percentile
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Frequently asked(5)

What is CVE-2023-33975?
CVE-2023-33975 is a critical-severity vulnerability; its CVE record was published on May 30, 2023. RIOT-OS, an operating system for Internet of Things (IoT) devices, contains a network stack with the ability to process 6LoWPAN frames. In version 2023.01 and prior, an attacker can send a crafted frame to the device resulting in an out of bounds write in the packet buffer. The overflow can be used…
When was the CVE record for CVE-2023-33975 published?
The CVE record for CVE-2023-33975 was published on May 30, 2023. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of November 21, 2024; the record at its source may have been updated since.
Is CVE-2023-33975 actively exploited?
CVE-2023-33975 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.5% probability of exploitation in the next 30 days (73rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2023-33975?
CVE-2023-33975 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2023-33975?
A fix for CVE-2023-33975 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

Dependency Blast Radius

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