CVE-2024-40640
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Usage of non-constant time base64 decoder could lead to leakage of secret key material in vodozemac
rank 7 = 0 + 7 + 0 + 0 + 0
rank@v1 · backlog
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.00201 · without this subject the record ranks 7
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 2.9, from the CNA · without this subject the record ranks 0
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
no persisting rise in 365 days · without this subject the record ranks 7
How much of the world it touches
NVD CPE configurations
0 products in the CPE ranges · without this subject the record ranks 7
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 7
$2,410 = $4.99M incident cost x 0.24048551839932833 exposure x 0.00201 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Hindsight · the state
Foresight · where to check next
No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.
Running matrix-org vodozemac? Check your version
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Harm, if it fires from the vector and the weakness
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CISA KEV & Federal Remediation Deadline from the record and CISA
The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Nothing observed in held sources.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published
- RUNG 3Exploited in the wild · CISA KEV listed
- RUNG 4Ransomware campaign use known
Affected & Fixed Versions as published
A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.
What it is stated by the CNA
vodozemac is an open source implementation of Olm and Megolm in pure Rust. Versions before 0.7.0 of vodozemac use a non-constant time base64 implementation for importing key material for Megolm group sessions and `PkDecryption` Ed25519 secret keys. This flaw might allow an attacker to infer some information about the secret key material through a side-channel attack. The use of a non-constant time base64 implementation might allow an attacker to observe timing variations in the encoding and decoding operations of the secret key material. This could potentially provide insights into the underlying secret key material. receipt
Read the rest of the CNA's description
The impact of this vulnerability is considered low because exploiting the attacker is required to have access to high precision timing measurements, as well as repeated access to the base64 encoding or decoding processes. Additionally, the estimated leakage amount is bounded and low according to the referenced paper. This has been patched in commit 734b6c6948d4b2bdee3dd8b4efa591d93a61d272 which has been included in release version 0.7.0. Users are advised to upgrade. There are no known workarounds for this vulnerability.
NVD's analysis a second authority
- weakness
- CWE-208
- also scored by
- [email protected] 2.9 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
check it yourself github.com github.com arxiv.org receipt
Movement the material steps
Show all 15 observations
15 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt
The full biography
The record had been public for 1 year, 10 months when this index was last written.
Siblings and hubs
Records related to this one
None. No alias set, and nothing in the corpus cites this identifier or shares its product family within 60 days.
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What usually comes next
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