CVE-2026-54874 (GCVE-0-2026-54874)

Vulnerability from cvelistv5 – Published: 2026-08-25 12:59 – Updated: 2026-08-25 14:28
VLAI
Title
Excessive Memory Use Buffering DTLS Records for a Future Epoch
Summary
Issue summary: Receiving a DTLS record for a future epoch while a handshake is in progress causes OpenSSL to buffer far more memory than the record itself requires. Impact summary: A peer can use a small amount of network traffic to make an OpenSSL DTLS endpoint retain a disproportionately large amount of memory, which may lead to a Denial of Service. CWE: CWE-405: Asymmetric Resource Consumption (Amplification) Description: While a DTLS handshake is in progress, a peer may legitimately have already moved on to the next epoch (for example, having sent its ChangeCipherSpec and Finished messages) before the local endpoint has processed the same transition, typically because of reordering on the underlying UDP transport. OpenSSL buffers such early records so that they can be processed once the local endpoint catches up. Buffering a record currently retains the entire read buffer it arrived in, which is sized to hold the largest possible DTLS record (around 16 kilobytes), rather than just the bytes that make up the record itself. Up to 100 such records may be buffered per connection. As a result, a peer that sends a stream of small forged records claiming to belong to the next epoch can cause an OpenSSL DTLS endpoint to retain around 1.7 megabytes of memory, despite sending only a small fraction of that amount of data over the network. An attacker therefore gains a memory amplification factor of around 1200, and can multiply the effect across as many associations as it is able to open, making this a remote memory exhaustion Denial of Service risk for DTLS servers. Since the memory retained per connection remains bounded, and any limit an application already places on the number of concurrent associations also bounds the total exposure, this issue has been assessed as Low severity. FIPS impact: no No FIPS modules are affected by this issue as the affected code is outside the OpenSSL FIPS module boundary. OpenSSL 4.0, 3.6, 3.5, 3.4, 3.0, 1.1.1 and 1.0.2 are vulnerable to this issue. OpenSSL 4.0 users should upgrade to OpenSSL 4.0.2. OpenSSL 3.6 users should upgrade to OpenSSL 3.6.4. OpenSSL 3.5 users should upgrade to OpenSSL 3.5.8. OpenSSL 3.4 users should upgrade to OpenSSL 3.4.7. OpenSSL 3.0 users should upgrade to OpenSSL 3.0.22. Premium support customers only: OpenSSL 1.1.1 users should upgrade to OpenSSL 1.1.1zi OpenSSL 1.0.2 users should upgrade to OpenSSL 1.0.2zr This issue was reported on 18 May 2026 by Amazon Web Services. The fix has been developed by Matt Caswell. -- cut (non-publishing metadata for internal use) -- Reported by: Amazon Web Services Fixed by: Matt Caswell
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-25 14:28 UTC
CWE
  • CWE-405 - Asymmetric Resource Consumption (Amplification)
Assigner
References
Impacted products
Vendor Product Version CPE status
OpenSSL OpenSSL Affected: 4.0.0 , < 4.0.2 (semver)
Affected: 3.6.0 , < 3.6.4 (semver)
Affected: 3.5.0 , < 3.5.8 (semver)
Affected: 3.4.0 , < 3.4.7 (semver)
Affected: 3.0.0 , < 3.0.22 (semver)
Affected: 1.1.1 , < 1.1.1zi (custom)
Affected: 1.0.2 , < 1.0.2zr (custom)
guessed Create a notification for this product.
Date Public
2026-08-25 11:36
Credits
Amazon Web Services Matt Caswell
Show details on NVD website
To clipboard 

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      "source": "Red Hat CSAF VEX",
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      "title": "openssl: excessive memory use buffering DTLS records for a future epoch",
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    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-54874\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-08-25T14:28:32.620361Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-08-25T14:28:29.699Z\"}}], \"cna\": {\"title\": \"Excessive Memory Use Buffering DTLS Records for a Future Epoch\", \"source\": {\"discovery\": \"UNKNOWN\"}, \"credits\": [{\"lang\": \"en\", \"type\": \"reporter\", \"value\": \"Amazon Web Services\"}, {\"lang\": \"en\", \"type\": \"remediation developer\", \"value\": \"Matt Caswell\"}], \"metrics\": [{\"other\": {\"type\": \"https://openssl-library.org/policies/general/security-policy/\", \"content\": {\"text\": \"Low\"}}, \"format\": \"other\"}], \"affected\": [{\"vendor\": \"OpenSSL\", \"product\": \"OpenSSL\", \"versions\": [{\"status\": \"affected\", \"version\": \"4.0.0\", \"lessThan\": \"4.0.2\", \"versionType\": \"semver\"}, {\"status\": \"affected\", \"version\": \"3.6.0\", \"lessThan\": \"3.6.4\", \"versionType\": \"semver\"}, {\"status\": \"affected\", \"version\": \"3.5.0\", \"lessThan\": \"3.5.8\", \"versionType\": \"semver\"}, {\"status\": \"affected\", \"version\": \"3.4.0\", \"lessThan\": \"3.4.7\", \"versionType\": \"semver\"}, {\"status\": \"affected\", \"version\": \"3.0.0\", \"lessThan\": \"3.0.22\", \"versionType\": \"semver\"}, {\"status\": \"affected\", \"version\": \"1.1.1\", \"lessThan\": \"1.1.1zi\", \"versionType\": \"custom\"}, {\"status\": \"affected\", \"version\": \"1.0.2\", \"lessThan\": \"1.0.2zr\", \"versionType\": \"custom\"}], \"defaultStatus\": \"unaffected\"}], \"datePublic\": \"2026-08-25T11:36:16.000Z\", \"references\": [{\"url\": \"https://openssl-library.org/news/secadv/20260825.txt\", \"name\": \"OpenSSL Advisory\", \"tags\": [\"vendor-advisory\"]}, {\"url\": \"https://github.com/openssl/openssl/commit/cc0c6710917cd5eec001b297355d2ba723505107\", \"name\": \"4.0.2 git commit\", \"tags\": [\"patch\"]}, {\"url\": \"https://github.com/openssl/openssl/commit/f52ffc11b90737ac89083909618dc2e1f42c561c\", \"name\": \"3.6.4 git commit\", \"tags\": [\"patch\"]}, {\"url\": \"https://github.com/openssl/openssl/commit/4808b5d64176451f3d93d87d0ac9c81a9b13fb23\", \"name\": \"3.5.8 git commit\", \"tags\": [\"patch\"]}, {\"url\": \"https://github.com/openssl/openssl/commit/7110cb2f75806d0bf809eb2f90790d477900be40\", \"name\": \"3.4.7 git commit\", \"tags\": [\"patch\"]}, {\"url\": \"https://github.com/openssl/openssl/commit/a0c8ec557d9cac078f032d76cdf684fe743eb382\", \"name\": \"3.0.22 git commit\", \"tags\": [\"patch\"]}], \"x_generator\": {\"engine\": \"Vulnogram 0.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"Issue summary: Receiving a DTLS record for a future epoch while a handshake\\nis in progress causes OpenSSL to buffer far more memory than the record\\nitself requires.\\n\\nImpact summary: A peer can use a small amount of network traffic to make an\\nOpenSSL DTLS endpoint retain a disproportionately large amount of memory,\\nwhich may lead to a Denial of Service.\\n\\nCWE: CWE-405: Asymmetric Resource Consumption (Amplification)\\n\\nDescription: While a DTLS handshake is in progress, a peer may legitimately\\nhave already moved on to the next epoch (for example, having sent its\\nChangeCipherSpec and Finished messages) before the local endpoint has\\nprocessed the same transition, typically because of reordering on the\\nunderlying UDP transport. OpenSSL buffers such early records so that they\\ncan be processed once the local endpoint catches up.\\n\\nBuffering a record currently retains the entire read buffer it arrived in,\\nwhich is sized to hold the largest possible DTLS record (around 16\\nkilobytes), rather than just the bytes that make up the record itself. Up\\nto 100 such records may be buffered per connection. As a result, a peer\\nthat sends a stream of small forged records claiming to belong to the next\\nepoch can cause an OpenSSL DTLS endpoint to retain around 1.7 megabytes of\\nmemory, despite sending only a small fraction of that amount of data over\\nthe network.\\n\\nAn attacker therefore gains a memory amplification factor of around 1200,\\nand can multiply the effect across as many associations as it is able to\\nopen, making this a remote memory exhaustion Denial of Service risk for\\nDTLS servers. Since the memory retained per connection remains bounded,\\nand any limit an application already places on the number of concurrent\\nassociations also bounds the total exposure, this issue has been assessed\\nas Low severity.\\n\\nFIPS impact: no\\n\\nNo FIPS modules are affected by this issue as the affected code is outside\\nthe OpenSSL FIPS module boundary.\\n\\nOpenSSL 4.0, 3.6, 3.5, 3.4, 3.0, 1.1.1 and 1.0.2 are vulnerable to this\\nissue.\\n\\nOpenSSL 4.0 users should upgrade to OpenSSL 4.0.2.\\nOpenSSL 3.6 users should upgrade to OpenSSL 3.6.4.\\nOpenSSL 3.5 users should upgrade to OpenSSL 3.5.8.\\nOpenSSL 3.4 users should upgrade to OpenSSL 3.4.7.\\nOpenSSL 3.0 users should upgrade to OpenSSL 3.0.22.\\n\\nPremium support customers only:\\nOpenSSL 1.1.1 users should upgrade to OpenSSL 1.1.1zi\\nOpenSSL 1.0.2 users should upgrade to OpenSSL 1.0.2zr\\n\\nThis issue was reported on 18 May 2026 by Amazon Web Services.\\nThe fix has been developed by Matt Caswell.\\n\\n-- cut (non-publishing metadata for internal use) --\\nReported by: Amazon Web Services\\nFixed by: Matt Caswell\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"Issue summary: Receiving a DTLS record for a future epoch while a handshake\u003cbr\u003eis in progress causes OpenSSL to buffer far more memory than the record\u003cbr\u003eitself requires.\u003cbr\u003e\u003cbr\u003eImpact summary: A peer can use a small amount of network traffic to make an\u003cbr\u003eOpenSSL DTLS endpoint retain a disproportionately large amount of memory,\u003cbr\u003ewhich may lead to a Denial of Service.\u003cbr\u003e\u003cbr\u003eCWE: CWE-405: Asymmetric Resource Consumption (Amplification)\u003cbr\u003e\u003cbr\u003eDescription: While a DTLS handshake is in progress, a peer may legitimately\u003cbr\u003ehave already moved on to the next epoch (for example, having sent its\u003cbr\u003eChangeCipherSpec and Finished messages) before the local endpoint has\u003cbr\u003eprocessed the same transition, typically because of reordering on the\u003cbr\u003eunderlying UDP transport. OpenSSL buffers such early records so that they\u003cbr\u003ecan be processed once the local endpoint catches up.\u003cbr\u003e\u003cbr\u003eBuffering a record currently retains the entire read buffer it arrived in,\u003cbr\u003ewhich is sized to hold the largest possible DTLS record (around 16\u003cbr\u003ekilobytes), rather than just the bytes that make up the record itself. Up\u003cbr\u003eto 100 such records may be buffered per connection. As a result, a peer\u003cbr\u003ethat sends a stream of small forged records claiming to belong to the next\u003cbr\u003eepoch can cause an OpenSSL DTLS endpoint to retain around 1.7 megabytes of\u003cbr\u003ememory, despite sending only a small fraction of that amount of data over\u003cbr\u003ethe network.\u003cbr\u003e\u003cbr\u003eAn attacker therefore gains a memory amplification factor of around 1200,\u003cbr\u003eand can multiply the effect across as many associations as it is able to\u003cbr\u003eopen, making this a remote memory exhaustion Denial of Service risk for\u003cbr\u003eDTLS servers. Since the memory retained per connection remains bounded,\u003cbr\u003eand any limit an application already places on the number of concurrent\u003cbr\u003eassociations also bounds the total exposure, this issue has been assessed\u003cbr\u003eas Low severity.\u003cbr\u003e\u003cbr\u003eFIPS impact: no\u003cbr\u003e\u003cbr\u003eNo FIPS modules are affected by this issue as the affected code is outside\u003cbr\u003ethe OpenSSL FIPS module boundary.\u003cbr\u003e\u003cbr\u003eOpenSSL 4.0, 3.6, 3.5, 3.4, 3.0, 1.1.1 and 1.0.2 are vulnerable to this\u003cbr\u003eissue.\u003cbr\u003e\u003cbr\u003eOpenSSL 4.0 users should upgrade to OpenSSL 4.0.2.\u003cbr\u003eOpenSSL 3.6 users should upgrade to OpenSSL 3.6.4.\u003cbr\u003eOpenSSL 3.5 users should upgrade to OpenSSL 3.5.8.\u003cbr\u003eOpenSSL 3.4 users should upgrade to OpenSSL 3.4.7.\u003cbr\u003eOpenSSL 3.0 users should upgrade to OpenSSL 3.0.22.\u003cbr\u003e\u003cbr\u003ePremium support customers only:\u003cbr\u003eOpenSSL 1.1.1 users should upgrade to OpenSSL 1.1.1zi\u003cbr\u003eOpenSSL 1.0.2 users should upgrade to OpenSSL 1.0.2zr\u003cbr\u003e\u003cbr\u003eThis issue was reported on 18 May 2026 by Amazon Web Services.\u003cbr\u003eThe fix has been developed by Matt Caswell.\u003cbr\u003e\u003cbr\u003e-- cut (non-publishing metadata for internal use) --\u003cbr\u003eReported by: Amazon Web Services\u003cbr\u003eFixed by: Matt Caswell\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-405\", \"description\": \"CWE-405 Asymmetric Resource Consumption (Amplification)\"}]}], \"providerMetadata\": {\"orgId\": \"3a12439a-ef3a-4c79-92e6-6081a721f1e5\", \"shortName\": \"openssl\", \"dateUpdated\": \"2026-08-25T12:59:17.912Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-54874\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-25T14:28:37.339Z\", \"dateReserved\": \"2026-06-16T10:18:08.635Z\", \"assignerOrgId\": \"3a12439a-ef3a-4c79-92e6-6081a721f1e5\", \"datePublished\": \"2026-08-25T12:59:17.912Z\", \"assignerShortName\": \"openssl\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.