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CVE-2026-8796

📛 CVE Title

Sereal::Decoder versions before 5.005 for Perl allow heap out-of-bounds read via crafted input

⬇ Download JSON ⚠ View as Threat

Description

Sereal::Decoder versions before 5.005 for Perl allow heap out-of-bounds read via crafted input. In Perl/Decoder/srl_decoder.c, srl_read_object() and srl_read_hash() process a COPY tag, a back-reference whose target byte the decoder re-decodes as a fresh tag. When that target byte matches the SHORT_BINARY pattern (an inline string whose length is encoded in the low bits of the tag), the resulting read is not bounded to precede the COPY tag's own offset and can run past the end of the input buffer. An attacker controlled COPY offset can land inside a previously decoded value rather than on a tag boundary, planting a byte that the decoder reads as a SHORT_BINARY tag and consuming up to 31 following bytes from the heap as a class name (OBJECT path) or hash key (HASH path).

Overview

State
PUBLISHED
Assigner (CNA)
CPANSec
CVSS severity
high
CVSS score
CVSS 8.1 / 10 8.1 8.1 / 10
CVSS vector
AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
Effective score
8.1 / 10 HIGH source: CNA overview
CWE(s)
CWE-125
Reserved
2026-05-18
Published
2026-05-31 19:43 UTC
Last updated
2026-06-01 18:42 UTC
Source
https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/8xxx/CVE-2026-8796.json
Linked Threat
CVE-2026-8796 — CVE-2026-8796

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published
2026-05-31 20:16:30 UTC
NVD last modified
2026-07-22 07:10:00 UTC
NVD CVSS v3.1
CVSS 8.1 / 10 8.1 8.1 / 10 HIGH source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
Exploitability subscore
2.8 / 10
Impact subscore
5.2 / 10
EPSS score
0.0040 (probability of exploitation in next 30 days)
EPSS percentile
32.60% vs all CVEs — higher = more likely to be exploited, as of 2026-07-28

NVD / KEV / EPSS data refreshed 2026-07-28 15:08 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID
EUVD-2026-33517
Assigner
CPANSec
Published
May 31, 2026, 7:43:22 PM
Updated
Jun 1, 2026, 6:42:31 PM
EUVD base score (CVSS 3.1)
8.1 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
EUVD-reported EPSS
0.4000
Vendors
YVES
Products
Sereal::Decoder (0 <5.005)
Aliases
GHSA-xhpj-269v-vq2q

ENISA description: Sereal::Decoder versions before 5.005 for Perl allow heap out-of-bounds read via crafted input. In Perl/Decoder/srl_decoder.c, srl_read_object() and srl_read_hash() process a COPY tag, a back-reference whose target byte the decoder re-decodes as a fresh tag. When that target byte matches the SHORT_BINARY pattern (an inline string whose length is encoded in the low bits of the tag), the resulting read is not bounded to precede the COPY tag's own offset and can run past the end of the input buffer. An attacker controlled COPY offset can land inside a previously decoded value rather than on a tag boundary, planting a byte that the decoder reads as a SHORT_BINARY tag and consuming up to 31 following bytes from the heap as a class name (OBJECT path) or hash key (HASH path).

EUVD references (2)

Affected products (1)
VendorProductVersionsPlatforms
YVES Sereal::Decoder 0 (affected) —

Vendor references (2)

References embedded in the original CVE record by the assigning CNA.

Web references (6)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

NVD-tagged references (3)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

Remediations (19)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-8796.json.

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2026-06-01T07:44:02.734Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/06/01/1"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 8.1,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "REQUIRED",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-8796",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-01T18:42:19.702527Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-01T18:42:31.783Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "packageName": "Sereal-Decoder",
          "product": "Sereal::Decoder",
          "programFiles": [
            "Perl/Decoder/srl_decoder.c"
          ],
          "programRoutines": [
            {
              "name": "srl_read_object()"
            },
            {
              "name": "srl_read_hash()"
            }
          ],
          "repo": "https://github.com/Sereal/Sereal",
          "vendor": "YVES",
          "versions": [
            {
              "lessThan": "5.005",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
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          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Sereal::Decoder versions before 5.005 for Perl allow heap out-of-bounds read via crafted input.\n\nIn Perl/Decoder/srl_decoder.c, srl_read_object() and srl_read_hash() process a COPY tag, a back-reference whose target byte the decoder re-decodes as a fresh tag. When that target byte matches the SHORT_BINARY pattern (an inline string whose length is encoded in the low bits of the tag), the resulting read is not bounded to precede the COPY tag's own offset and can run past the end of the input buffer. An attacker controlled COPY offset can land inside a previously decoded value rather than on a tag boundary, planting a byte that the decoder reads as a SHORT_BINARY tag and consuming up to 31 following bytes from the heap as a class name (OBJECT path) or hash key (HASH path)."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-125",
              "description": "CWE-125 Out-of-bounds Read",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-31T19:43:22.054Z",
        "orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
        "shortName": "CPANSec"
      },
      "references": [
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/Sereal/Sereal/commit/303a2c69cdba80bf37a3ff43461e0aa78198a7a3.patch"
        },
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://metacpan.org/release/YVES/Sereal-Decoder-5.005/changes"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Upgrade to Sereal::Decoder 5.005 or later."
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "timeline": [
        {
          "lang": "en",
          "time": "2026-05-13T00:00:00.000Z",
          "value": "Issue reported."
        },
        {
          "lang": "en",
          "time": "2026-05-19T00:00:00.000Z",
          "value": "Fix released in Sereal::Decoder 5.005."
        },
        {
          "lang": "en",
          "time": "2026-05-20T00:00:00.000Z",
          "value": "Fix verified against proofs of concept."
        }
      ],
      "title": "Sereal::Decoder versions before 5.005 for Perl allow heap out-of-bounds read via crafted input",
      "x_generator": {
        "engine": "cpansec-cna-tool 0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
    "assignerShortName": "CPANSec",
    "cveId": "CVE-2026-8796",
    "datePublished": "2026-05-31T19:43:22.054Z",
    "dateReserved": "2026-05-18T00:38:16.965Z",
    "dateUpdated": "2026-06-01T18:42:31.783Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}